Full opinion text
TRASK, Circuit Judge: Frank Stearns Giese appeals from his conviction for conspiracy to commit offenses against the United States. We affirm. I Early on the morning of January 2, 1973, a bomb exploded at a United States Navy recruiting center in Portland, Oregon. Two days later a United States Army recruiting center in that city was dynamited. These acts of terrorism were perpetrated in furtherance of a well-organized conspiracy, the objects of which were to dramatize the conspirators’ opposition to America’s participation in the Vietnam War and to disrupt military operations in the Portland area. The evidence showed that Giese played a leading role in the conspiracy. Giese, a professor of French at Portland State University, met some of his co-eonspirators through the Radical Education Project bookstore which he founded in the fall of 1971. He sent books to prisoners at the Oregon State Correctional Institution, and in January 1972 he and James Cronin, who also worked at the bookstore, began leading group discussion sessions at the prison. The inmate participants included Lynn Meyer, Max Severin, and Chester Wallace. Meyer contacted Giese at the bookstore shortly after he was released from prison on furlough in November 1972. Giese introduced him to various people, one of whom was Leslie McKeel. She, in turn, introduced Meyer to Robert McSherry, James Akers, and several others. McKeel, McSherry, Akers, and Cronin jointly operated the Sundahl Painting Company. Meyer went to work for the company after receiving his parole on December 5, 1972. The Sundahl employees held business meetings and political discussions at Giese’s bookstore. Akers and Severin, along with Cronin, worked there part-time. McSherry and Meyer were the government’s principal witnesses at trial. According to McSherry, the discussions at Giese’s bookstore and elsewhere centered around the participants’ vehement opposition to the Vietnam War. Eventually they grew tired of doing nothing but talk; they decided there was a need for direct action. On December 10, 1972, McSherry, Wallace, Severin, McKeel, Akers, Meyer, and two others held a five-hour meeting at Giese’s farm. Giese greeted them but did not take part in the discussion. They agreed, as McSherry put it, “to do everything within [their] power to stop the war, to disrupt the war for at least as far as Portland went and as much as [they] possibly could.” R.T. at 547. Believing violence was necessary to accomplish this end, they discussed bombing recruiting centers, robbing National Guard depots, and other crimes. At this stage Giese had not yet agreed to finance the conspirators’ operations. Needing money with which to buy weapons, they devised a plan to burglarize the residence of a wealthy Portland industrialist named Ira Keller. The attempted break-in took place on December 12, 1972, two days after the meeting at Giese’s farm. Giese had become a full-fledged participant in the conspiracy by this time. According to McSherry, he drove several of his fellow conspirators to the Keller residence in a rented van. When McSherry, Wallace, Severin, and Akers tried to enter the house, an alarm sounded and everyone fled. The following day Giese met with Akers, Severin, McKeel, Wallace, Cronin and two others at Cronin’s apartment. They discussed the abortive Keller burglary, and Giese blamed their failure on a gross lack of planning. The conspirators’ next act of violence was arranged with greater care. While McSherry, Cronin, and Akers studied a book called the Blaster’s Handbook to learn bombing techniques, Severin and McKeel obtained some dynamite. On January 2, 1973, Wallace, Cronin, Akers, Meyer and McSherry committed the Navy recruiting center bombing. There is no evidence that Giese actively participated in the January 2nd bombing. However, at a four-hour meeting held at his apartment on January 3, 1973, he expressed approval of what the bombers had done, although he criticized them for selecting a target in a low-income neighborhood. He suggested that terrorist activities directed against recruiting centers in downtown Portland or in the white suburbs would win more popular support. When he was informed that the next bombing target — an Army recruiting center— satisfied his criteria, Giese agreed to take part, and he helped to plan the operation. He also promised his confederates enough money to buy a vehicle and rent a hideout for storing explosives, ammunition, and stolen weapons. McSherry and Meyer testified that early on the morning of January 4, 1973, Giese drove them and Akers to the Army recruiting center. Giese remained in his car while McSherry and Akers planted the explosives and Meyer stood watch. Meyer carried a pistol given him by Giese, and Giese was armed with a .38 caliber revolver. Their mission accomplished, Giese drove the bombers back to his apartment where they celebrated after learning that the bomb had exploded. McSherry and Meyer testified that the conspirators used money given them by Giese to rent an apartment on Ankeny Street in Portland which they used as a headquarters. Meyer said Giese also gave them firearms, including an M — 1 carbine. On January 8,1973, Giese met with McKeel, Severin, Wallace, Meyer, Akers, McSherry and Cronin at the Ankeny Street apartment. They discussed plans to rob a gun store. According to McSherry, Giese told them they were trying to do too much, too soon, and he urged them to split up and go underground for a while. When some of the others indicated their intention to go ahead with the gun store robbery, Giese refused to participate. He saw McSherry and the others again on January 13, 1973, outside the Ankeny Street apartment and at his farm. Giese was told that the conspirators would be arming themselves in the near future, and he again urged them to go underground. So far as the record shows, Giese did not take part in the gang’s robbery of the Allison and Carey Gunworks in Portland on January 15, 1973, their robbery of a bank, their plot to rob a restaurant and blow up a sheriff’s office, or their other crimes. II On February 28, 1974, a federal grand jury for the District of Oregon returned a joint ten-count indictment charging Giese, Akers, Cronin, Meyer, and Wallace with a variety of offenses and listing McKeel, McSherry, Severin, and one other person as unindicted co-conspirators. Giese was named in six of the counts. Count IV charged him with misprision of a felony (the January 2, 1973, Navy recruiting center bombing). Counts V through VIII charged him with committing various offenses in connection with the January 4, 1973, Army recruiting center bombing, including possession of destructive devices, malicious destruction of government property, carrying firearms during the commission of a felony, and injury to government property worth more than $100. Paragraph one of Count X, which alleged a violation of 18 U.S.C. § 371, said Giese, the other defendants, and the unindicted co-conspirators “did unlawfully, wilfully and knowingly conspire, combine, confederate, and agree together and with each other ... to commit and cause to be committed certain offenses against the United States and other persons and institutions by means of acts of violence, terrorism and disruption, including the use of explosives to damage and destroy and to attempt to damage and destroy certain real and personal property, both public and private, including the property described in Counts II and VI of this Indictment which are realleged and incorporated herein by reference.” Count II alleged the malicious destruction of the Navy recruiting center and Count VI alleged the malicious destruction of the Army recruiting center. Prior to trial, Meyer entered a plea of guilty to the conspiracy charge and agreed to testify as a government witness. Conspiracy charges against Akers and Wallace were dismissed, as was the Count IV misprision charge against Giese. On October 16, 1974, the jury found Akers and Wallace guilty on Counts I through III and Counts V through VIII and found Cronin guilty on Counts I through III and Count X. The jury acquitted Giese on Counts V through VII but found him guilty on Count X (conspiracy). Because Giese did not file his appellate brief on time, this court severed his case from the appeals of the other defendants. On August 26, 1976, we affirmed in part and vacated in part the convictions of Akers, Cronin, and Wallace. Cronin’s conviction for conspiracy was affirmed. United States v. Akers, 542 F.2d 770 (9th Cir. 1976). In challenging his conviction for conspiracy, Giese raises six separate issues: (1) Was Count X of the indictment legally sufficient? (2) Did the district court err in denying Giese’s motions for bills of particulars? (3) Was the voir dire examination adequate? (4) Did the court err in admitting certain evidence? (5) Were the court’s instructions to the jury erroneous? (6) Did the government commit reversible acts of prosecutorial misconduct? Ill Appellant Giese contends that his conviction must be reversed because the conspiracy charge against him was vague and overbroad, thereby depriving him of fair notice of the accusation against him and permitting the jury to return a guilty verdict based on conduct not violating federal law. He makes three arguments attacking the sufficiency of the conspiracy count. First, he asserts that the indictment failed to specify adequately the offenses which were the object of the conspiracy. He says the indictment’s incorporation of the federal offenses (the bombings) detailed in Counts II and VI did not exhaust the object offenses on which the jury could have based its conviction since the indictment also contained references to crimes against “other persons and institutions” and to the destruction of “public and private” property. A well-drafted indictment conveys important information to a defendant. In Russell v. United States, 369 U.S. 749, 763-64, 82 S.Ct. 1038, 1047, 8 L.Ed.2d 240 (1962), the Supreme Court outlined the two standards by which the adequacy of an indictment is to be evaluated: “These criteria are, first, whether the indictment ‘contains the elements of the offense intended to be charged, “and sufficiently apprises the defendant of what he must be prepared to meet,” ’ and secondly, ‘ “ ‘in case any other proceedings are taken against him for a similar offense, whether the record shows with accuracy to what extent he may plead a former acquittal or conviction’.” [Citations omitted.]’ ” An indictment charging a conspiracy under 18 U.S.C. § 371 satisfies these requirements if it alleges the three elements which are the gist of the offense: “the agreement, the unlawful object towards which the agreement is directed, and an overt act in furtherance of the conspiracy.” United States v. Charnay, 537 F.2d 341, 350 (9th Cir.), cert. denied, 429 U.S. 1000, 97 S.Ct. 528, 50 L.Ed.2d 610 (1976). Because “the conspiracy is the gist of the crime” in such an indictment, “it is not necessary to allege with technical precision all the elements essential to the commission of the offense which is the object of the conspiracy, or to state such object with the detail which would be required in an indictment for committing the substantive offense.” Wong Tai v. United States, 273 U.S. 77, 81, 47 S.Ct. 300, 301-2, 71 L.Ed. 545 (1927) (citations omitted). Applying these requirements to the present case, we reject appellant’s argument that Count X was vague and over-broad. “[A]n indictment is not to be read in a technical manner, but [it] is to be construed according to common sense with an appreciation of existing realities.” United States v. Anderson, 532 F.2d 1218, 1222 (9th Cir.), cert. denied, 429 U.S. 839, 97 S.Ct. 111, 50 L.Ed.2d 107 (1976). Such an interpretation of Count X persuades us that appellant’s fears and complaints are illusory. Considered as a whole, Count X adequately apprised Giese that the grand jury had found the two recruiting center bombings to be the primary object offenses of the conspiracy. The first paragraph of the count specifically referred to these offenses. The following three paragraphs stated that part of the conspiracy was for the defendants to carry firearms during the bombings and to construct the destructive devices used in the explosions. In addition, almost all the overt acts referred to by the indictment pertained to these federal offenses. After reading Count X, appellant could not possibly have been confused about what the government would attempt to prove at trial. As required by Russell v. United States, supra, 369 U.S. at 763, 82 S.Ct. 1038, he knew of the object offenses which he had to .defend against. Appellant urges that the broad language in Count X about offenses against “other persons and institutions” and damage to “public and private” property embraced unspecified object offenses such as the attempted burglary of Keller’s home and the robbery of the Allison and Carey Gunworks. This interpretation of the indictment is misguided. Since these acts are not federal offenses, it is unreasonable to assume that the indictment contained subtle, ambiguous references to crimes which could not properly be tried before a federal jury. Even if it did, however, this error was not fatal, for appellant was not on trial for conspiracy to commit non-federal offenses (specified or not in the indictment). He could not have been convicted on this basis, and he did not have to defend himself against these charges. A more natural construction of these words is that they referred to the damage to private property located near the recruiting centers which resulted from the excess force of the explosions. The indictment did not need to refer to damage to adjoining property (and to the individuals who owned it), but any overbreadth or vagueness created thereby was not prejudicial. The jury was able to focus on the federal object offenses, as indicated by its verdict finding appellant guilty of “conspiracy to commit certain offenses against the United States.” C.T. at 687. Second, appellant contends that because the indictment described offenses which were non-federal, “[t]he likelihood that the jury improperly convicted [him], at least in part, on the theory that he conspired to commit offenses against persons or property referred to by the evidence, but not cognizable as federal crimes, is quite strong . .” He asserts that the trial court’s failure to focus on the federal offenses in its instructions to the jury only increased the possibility of a conviction based on non-federal offenses. This argument is not convincing. As we have established, Count X of the indictment focused on federal offenses: the two bombings of the recruiting centers. Any reference to non-federal offenses were superfluous and harmless. Furthermore, even assuming that the indictment embraced non-federal offenses, the inclusion of a non-federal offense in a federal conspiracy indictment is permissible if the conspiracy also involves federal offenses. “A single conspiracy may have several purposes, but if one of them — whether primary or secondary — be the violation of a federal law, the conspiracy is unlawful under federal law.” Anderson v. United States, 417 U.S. 211, 226, 94 S.Ct. 2253, 2263, 41 L.Ed.2d 20 (1974). A conviction for such a conspiracy is valid as long as the court’s instructions inform the jury that the defendant’s guilt must be based on his agreement to commit at least one of the conspiracy’s objectives violating federal law. See United States v. Gallishaw, 428 F.2d 760, 763 (2d Cir. 1970). The trial court instructed the jury that the government was required to prove that appellant had conspired to commit federal offenses. The adequacy of this instruction (and an answer to appellant’s assertion that he was convicted of conspiring to commit non-federal offenses) is shown by the jury’s verdict, which found appellant guilty of “conspiracy to commit certain offenses against the United States.” C.T. at 687. Third, appellant objects to the section of the indictment which alleged that he conspired “to commit and cause to be committed certain offenses against the United ■States . . ..” After stating that “[tjhere is no such federal offense as conspiracy to aid and abet the commission of a crime or conspiracy to cause the commission of a crime,” he argues that the words “cause to be committed” impermissibly “allowed the jury to convict [him] of conspiracy on the basis that he merely aided and abetted criminal acts committed in furtherance of the conspiracy, rather than participating as a member of the conspiracy.” Appellant’s interesting theory is based on his contention that it is not a federal offense to conspire “to cause to be committed” a crime against the United States. His contention is erroneous, however, as a simple reading of the statutes involved in the conspiracy charge demonstrates. Destruction of government property by means of an explosive is a violation of 18 U.S.C. § 844(f), as alleged in Counts II and VI of the indictment. Conspiracy “to commit” any offense against the United States is a violation of 18 U.S.C. § 371; this violation was alleged in Count X. Since destruction of government property by explosives is an offense against the United States, clearly it is illegal to conspire “to commit” this act. Title 18 U.S.C. § 2(b) provides that “[w]hoever willfully causes an act to be done which if directly performed by him or another would be an offense against the United States, is punishable as a principal.” Combining this statute with 18 U.S.C. § 844(f), it follows that it is a federal offense to cause another person to destroy government property by means of an explosive. Because this act is an offense against the United States, it also follows that it is illegal under 18 U.S.C. § 371 to conspire “to cause to be committed” the destruction of government property by explosives. Thus, even if appellant had not participated directly in the January 4, 1973, bombing, the jury could have convicted him on Count X because of his participation in a conspiracy “to cause to be committed” this act of destruction. In United States v. Lupino, 480 F.2d 720, 724 (8th Cir.), cert. denied, 414 U.S. 924, 94 S.Ct. 257, 38 L.Ed.2d 159 (1973), the defendant offered a similar argument by contending that conspiracy “to cause” a felon to commit the substantive offense of receiving a firearm (18 U.S.C.App. § 1202(a)(1)) is not a violation of 18 U.S.C. § 371. The court concluded that “[t]his ingenious argument, in the final analysis, constitutes a futile exercise in semantics.” 480 F.2d at 724. We agree. IV Prior to trial, appellant and his co-defendants made two motions for bills of particulars. The first motion contained over 100 separate requests, and referred to all ten counts of the indictment. The second motion contained fewer requests, each of which was related to Count X. Citing the “ambiguities and uncertainties” of Count X, appellant’s second motion asked for a wide range of information, such as lists of conspiratorial acts performed by each person named in the indictment and of each overt act and object of the conspiracy. His first motion asked for even more specific information, such as how each of the 13 overt acts described in Count X contributed to the conspiracy and which oral statements made by the defendants created the conspiracy. Reiterating his theory advanced in section III, supra, that Count X of the indictment was vague and overbroad, he now argues that the court’s denial of these motions was reversible error. Rule 7(f) of the Federal Rules of Criminal Procedure provides for a bill of particulars: “The court may direct the filing of a bill of particulars. A motion for a bill of particulars may be made before arraignment or within ten days after arraignment or at such later time as the court may permit. A bill of particulars may be amended at any time subject to such conditions as justice requires.” The bill of particulars has three functions: “to inform the defendant of the nature of the charge against him with sufficient precision to enable him to prepare for trial, to avoid or minimize the danger of surprise at the time of trial, and to enable him to plead his acquittal or conviction in bar of another prosecution for the same offense when the indictment itself is too vague, and indefinite for such purposes.” United States v. Birmley, 529 F.2d 103, 108 (6th Cir. 1976). Accord, United States v. Andrino, 501 F.2d 1373, 1378 (9th Cir. 1974); Yeargain v. United States, 314 F.2d 881, 882 (9th Cir. 1963). The denial of a motion for a bill of particulars is within the discretion of the district court; its decision will not be disturbed absent an abuse of this discretion. United States v. Clay, 476 F.2d 1211, 1215 (9th Cir. 1973). We find that the denial of the motions was not an abuse of discretion. As discussed in section III, supra, Count X of the indictment was neither vague nor over-broad. It apprised appellant of the federal offense with which he was charged and of the overt acts which allegedly contributed to his participation in the conspiracy. “To the extent that the indictment or information itself provides details of the alleged offense, a bill of particulars is, of course, unnecessary.” 8 Moore’s Federal Practice ¶ 7.06[1] at 7-31 n.1 (2d ed. 1978). Furthermore, the government provided appellant with a large volume of information, including physical evidence offered at trial, grand jury testimony, and memoranda which revealed the government’s theory of the case. Full discovery also obviates the need for a bill of particulars. United States v. Clay, supra, 476 F.2d at 1215; 8 Moore’s Federal Practice ¶7.06(1) at 7—33. The information available to appellant was actually more than he had a right to demand, for there is no requirement in conspiracy cases that the government disclose even all the overt acts in furtherance of the conspiracy. United States v. Murray, 527 F.2d 401, 411 (5th Cir. 1976); United States v. Armocida, 515 F.2d 49, 54 (3d Cir.), cert. denied, 423 U.S. 858, 96 S.Ct. 111, 46 L.Ed.2d 84 (1975); United States v. Carroll, 510 F.2d 507, 509 (2d Cir. 1975), cert. denied, 426 U.S. 923, 96 S.Ct. 2633, 49 L.Ed.2d 378 (1976). Count X listed the 13 overt acts in furtherance of the conspiracy. Appellant’s request for the “when, where, and how” of every act in furtherance of the conspiracy was equivalent to a request for complete discovery of the government’s evidence, which is not a purpose of the bill of particulars. United States v. Armocida, supra, 515 F.2d at 54. “A defendant is not entitled to know all the evidence the government intends to produce, but only the theory of the government’s case.” Yeargain v. United States, supra, 314 F.2d at 882. From the indictment and the government evidence which he did receive, appellant learned enough of the charges against him to prepare for trial, to avoid surprise at trial, and to plead double jeopardy in the event of a new prosecution. V The Sixth Amendment requires that “[i]n all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury . . An examination or “voir dire” of prospective jurors helps to ensure that the defendant is tried by an impartial jury. Rule 24(a) of the Federal Rules of Criminal Procedure provides that the court may decide whether it or the parties’ counsel will conduct the examination. If the court conducts the voir dire, it “shall permit the defendant or his attorney and the attorney for the government to supplement the examination by such further inquiry as it deems proper or shall itself submit to the prospective jurors such additional questions by the parties or their attorneys as it deems proper.” Fed.R.Crim.P. 24(a). We have held that “the scope of the voir dire examination and the procedures to be used are matters within the sound discretion of the trial judge, and will not be disturbed on appeal unless the procedures used or the questions propounded are so unreasonable or devoid of the constitutional purpose as to constitute an abuse of that discretion.” Haslam v. United States, 431 F.2d 362, 364 (9th Cir.), cert. denied, 402 U.S. 976, 91 S.Ct. 1680, 29 L.Ed.2d 142 (1970). “It is not an abuse of discretion for the trial judge to insist upon conducting a voir dire examination, but if he does so, he must exercise a sound ‘judicial’ discretion in the acceptance or rejection of supplemental questions' proposed by counsel . . ..” Silverthorne v. United States, 400 F.2d 627, 638 (9th Cir. 1968). A. Juror Attitudes Appellant does not contest these principles or the decision of the court to conduct the voir dire examination. Rather, he contends that as a man of unpopular political views who found himself on trial for conspiracy to destroy military recruiting centers, he was entitled to discover prospective jurors’ attitudes toward law enforcement personnel, military personnel, the use of firearms, and the Vietnam War. He argues that the court’s perfunctory exploration of these topics, coupled with its refusal to submit defense counsel’s more probing questions to the jurors, was reversible error. The amount of time a trial court must spend inquiring into prospective jurors’ attitudes varies with each case. Most crimes are mundane, and require only a cursory voir dire examination. Crimes of bombing and terrorism, especially if' committed as a protest against governmental behavior, more easily arouse the prejudices of prospective jurors, however, and necessitate a more elaborate voir dire. Although appellant’s activities occurred in 1972 and 1973, near the termination of the Vietnam War, they might have inflamed the passions of at least several prospective jurors, rendering them incapable of performing fairly at his trial. Even in 1974, at the time of appellant’s trial, many Americans opposed any form of protest against the War, and a still greater number opposed the equation of violence with political expression. Some laypersons might have carried these attitudes with them into a trial of a man accused of conspiring to bomb military recruiting centers. Therefore, it was essential for the trial judge in the present case to examine prospective jurors’ attitudes toward appellant and the views he represented. The court thoroughly questioned the first prospective juror, and elicited information about his views toward law enforcement personnel, the armed forces, the use of firearms, Vietnam War protests, and his exposure to pretrial publicity. This inquiry was detailed and comprehensive, and it focused on the areas about which appellant desired information. After hearing this juror’s answers, appellant, the government, and the court knew with some certainty whether or not he was qualified to serve at the trial. The court’s examination of several other jurors was also beyond reproach. For some jurors, however, the court conducted a more limited inquiry, asking merely if a juror had any responses to questions that the court had asked other prospective jurors. In the interest of symmetry, a uniform examination of each juror might have been desirable. Our function is not to ascertain whether the voir dire met technical standards of perfection, however. We will not find an examination inadequate unless the district court abused its discretion by failing to ask questions capable of revealing the prejudices of the prospective jurors. In the present case, the court did not ask every juror specific questions about his or her attitudes toward law enforcement and military personnel, the use of firearms, and the Vietnam War. However, each juror was asked, at a minimum, to consider the more detailed questions directed at the previous jurors and to inform the court of any different responses which these queries elicited. After observing the amount of time required for a full-scale examination of each juror, the district court had the authority to adopt a more compact mode of inquiry. See Haslam v. United States, supra, 431 F.2d at 364. In United States v. Amaral, 488 F.2d 1148, 1150 (9th Cir. 1973), we approved a voir dire in which the court asked the first prospective juror a question about racial prejudice and thereafter “reminded the prospective jurors that all questions asked of one juror were asked of all and that the voir dire process was a cumulative one designed to probe into the juror’s state of mind to discover whether each could determine guilt or innocence based solely on the evidence presented at trial.” The questions propounded by the district court in United States v. Giese succeeded in ferreting out jurors who were incapable of serving impartially. In response to the court’s general question that incorporated the more specific questions asked of other jurors, several prospective jurors expressed strong feelings about law enforcement personnel and the Vietnam War. These jurors did not serve on the panel which tried appellant. At the close of the initial voir dire, the court permitted defense counsel to suggest additional questions to ask the jurors. Although the court refused to ask requested questions about President Ford’s conditional amnesty plan and his pardon of former President Nixon, it did honor most of the other requests. This procedure gave defense counsel an opportunity to participate in the voir dire and to ensure that jurors with questionable qualifications were eliminated. Appellant argues that the court erred in refusing to accept all his proposed questions, which he offered both before and during the examination. A district court has considerable discretion to accept or reject proposed questions, however, and as long as it conducts an adequate voir dire, its rejection of a defendant’s specific questions is not error. United States v. Heck, 499 F.2d 778, 790 (9th Cir.), cert. denied, 419 U.S. 1088, 95 S.Ct. 677, 42 L.Ed.2d 680 (1974); United States v. Hamling, 481 F.2d 307, 314 (9th Cir. 1973), aff’d. 418 U.S. 87, 94 S.Ct. 2887, 41 L.Ed.2d 590 (1974). The district court asked many of the questions suggested by appellant, but, to conserve time and avoid confusion, was justified in declining to ask the others. United States v. Workman, 454 F.2d 1124, 1128-29 (9th Cir.), cert. denied, 409 U.S. 857, 93 S.Ct. 138, 34 L.Ed.2d 102 (1972). Given the adequacy of the voir dire examination which it did conduct, we cannot say that the court erred in not using every question proposed by appellant: “The court closest to the situation can best evaluate the proper way to walk the difficult line between a vigorous voir dire to determine any possible bias and avoidance of creating bias by specific questions which add ‘fuel to the flames’ in suggesting the presence of controversial issues.” United States v. Polizzi, 500 F.2d 856, 880 (9th Cir. 1974), cert. denied, 419 U.S. 1120, 95 S.Ct. 802, 42 L.Ed.2d 820 (1975). B. Pretrial Publicity Appellant also argues that the district court failed to safeguard his right to an impartial jury uninfluenced by prejudicial pretrial publicity. He contends that massive publicity surrounded his indictment, necessitating a detailed inquiry into the exposure of each prospective juror to media coverage. The trial court’s cursory probe into this subject, he concludes, did not dispel the substantial possibility that he was tried by jurors who formed their opinions prior to trial. Perhaps to the misfortune of everyone involved in the judicial process, no precise rule prescribes the type of voir dire examination which is necessary to protect against prejudicial pretrial publicity. The appropriate scope and detail of the voir dire depend on the level of pretrial publicity and the discretion of the district court. When “pretrial publicity is great, the trial judge must exercise correspondingly great care in all aspects of the case relating to publicity which might tend to defeat or impair the rights of an accused.” Silverthorne v. United States, supra, 400 F.2d at 637-38. The voir dire “must not simply call for the jurors’ subjective assessment of their own impartiality, and it must riot be so general that it does not adequately probe the possibility of prejudice.” United States v. Polizzi, supra, 500 F.2d at 879. The district court should conduct a careful, individual examination of each prospective juror, preferably out of the presence of the other jurors. A general question directed to the entire group of prospective jurors is inadequate. See id. at 879-80; Silverthorne v. United States, supra, 400 F.2d at 638-40; ABA Standards Relating to Fair Trial and Free Press § 3.4(a) at 130 (Approved Draft, 1968). In cases of less publicity, however, these procedures are not required. Several general questions addressed to the entire panel of jurors, followed by individual questioning of jurors who respond affirmatively to the initial inquiries, may be sufficient if it becomes clear that few jurors have any knowledge of the case. See United States v. Liddy, 166 U.S.App.D.C. 95, 103-104, 509 F.2d 428, 436-37 (1974), cert. denied, 420 U.S. 911, 95 S.Ct. 833, 42 L.Ed.2d 842 (1975); United States v. Polizzi, supra, 500 F.2d at 879-80. Similarly, the court initially may ask several jurors specific questions about their exposure to pretrial publicity, and, once it is apparent that they know little or nothing about the case, may direct more general questions, incorporating all the questions asked previously to the remaining jurors. Since the district court confronts a difficult task in assessing the type of voir dire which is necessary, the responses of the first jurors queried can serve as an indication, at least as reliable as other subjective evaluations, of the amount of publicity the case has generated. In the present case, the court asked approximately half the potential jurors, most of whom were among the first jurors questioned, about their exposure to pretrial publicity. Almost every juror had little or no prior knowledge of appellant’s indictment, arrest, and pending trial. Jurors who stated that they had formed opinions about the case did not serve on the trial jury. The remaining jurors were asked more general questions about their ability to serve impartially. Again, however, jurors who expressed opinions about the case were excused. The district court did not abuse its discretion by the manner in which it disposed of the pretrial publicity question. “Unless a trial judge clearly has erred in his estimation of the action needed to uncover and prevent prejudice from pretrial publicity, an appellate court should not intervene and impose its estimate.” United States v. Polizzi, supra, 500 F.2d at 880. By its own observation of media coverage of appellant’s case, the district court was able to determine the level of publicity surrounding the trial and the care required to screen out biased jurors. We are not in a position to assess more accurately how many headlines, editorials, and photographs the media devoted to appellant’s activities, arrest, and trial. The absence of a significant number of jurors who were influenced by, or had even seen, coverage of appellant’s case in newspapers and on radio and television reinforced the court’s evaluation of this prosecution as one in which a highly intensive probe of each juror was unnecessary. Only in a case involving extreme pretrial publicity, with demonstrated effects on the prospective jurors, have we held that a trial court’s voir dire was inadequate. In Silverthorne v. United States, supra, 400 F.2d at 635, 639, all 65 veniremen admitted hearing about the case, and 30 percent of these panelists had formed an opinion about the defendant’s guilt or innocence. We found that “under the peculiar and difficult facts of this case,” the court had abused its discretion by conducting a cursory voir dire examination. Id. at 640. The factual pattern of United States v. Giese more closely resembles that of United States v. Polizzi, supra, however. In Polizzi, there had been some coverage of the defendant’s trial, but the “trial judge’s questions on pretrial publicity were limited to two questions addressed to the first prospective panel of jurors and later questions addressed to an individual prospective juror.” Id. at 879-80 (footnotes omitted). Because the answers to these questions gave no indication of possible prejudice, we found the voir dire adequate. We make a comparable finding in the present case. VI A. From the Movement Toward Revolution Giese claims the trial judge committed three separate errors in permitting the government to use a book entitled From the Movement Toward Revolution as evidence against him. First, he argues that it was error to admit the book in the prosecution’s case-in-chief for the purpose of showing the association between Giese and the other conspirators because its prejudicial effect outweighed its probative value. Second, he says the book’s contents should never have been revealed to the jury because they were hearsay and irrelevant to the offense charged. Third, he argues that it was improper for the court to permit the prosecutor to ask Giese to read allegedly inflammatory passages from the book in front of the jury. Giese contends that in addition to violating the rules of evidence, admission of From the Movement Toward Revolution infringed his First Amendment liberties, including freedom of expression and the right to receive information. We reject Giese’s arguments, but in so doing we wish to emphasize that we are not establishing a general rule that the government may use a person’s reading habits, literary tastes, or political views as evidence against him in a criminal prosecution. In many cases such evidence would be clearly inadmissible. See, e. g., United States v. McCrea, 583 F.2d 1083 (9th Cir. 1978). Our decision upholding the admissibility of From the Movement Toward Revolution stems from the peculiar circumstances of this case and, reflecting our concern for the sensitive nature of First Amendment values, it rests on very narrow grounds. We hold that it was proper to introduce the book during the government’s case-in-chief because it bore the fingerprints of Giese and three of his co-conspirators and thus tended to corroborate witnesses’ testimony that the conspirators associated with each other. We further hold that it was proper to ask Giese to read extracts from the book on cross-examination because he opened the door to that line of inquiry by introducing 18 books as evidence of his peaceable character during his own testimony on direct examination. At the outset we must clearly distinguish between the book as a physical object which bore certain fingerprints and the book as a work of literature which contained a particular message. During the government’s case-in-chief not a single word was said by the prosecutors or by any government witness regarding the book’s contents. From the Movement Toward Revolution was used solely for the limited and permissible purpose of proving association. Co-conspirator McSherry testified that the book — Government Exhibit C-49 — belonged to co-conspirator Severin, R.T. at 672, and co-conspirator Meyer said he had seen it in the possession of various conspirators at apartments in Portland and Seattle. R.T. at 996. The prosecution and defense attorneys stipulated that FBI agent Frank Doyle would testify that he seized the book during the search of a San Jose, California apartment occupied by co-conspirators McKeel, Severin, and Wallace. Following the stipulation, Exhibit C — 49 was received in evidence along with 26 other items which had been seized in San Jose. R.T. at 1290-91. Exhibit C-49 was linked to individual conspirators when FBI fingerprint expert Richard Ranels testified that fingerprints found on the book matched those on exemplars furnished by Giese, Wallace, Severin, and McKeel. R.T. at 1510-14. On appeal Giese argues that the book had “virtually no probative value as evidence” of association, and what little value it did have was “substantially outweighed by the danger of unfair prejudice, of confusion of the issues, or of misleading the jury.” Appellant’s Brief at 44-45. No such objection was made at any point during the government’s case-in-chief. Nor did Giese’s attorney request a limiting or cautionary instruction when the book was received in evidence. Consequently, we must apply a plain error standard of review to Giese’s appellate argument that the book was inadmissible as proof of association. We hold that the court below did not plainly err in permitting the prosecution to introduce From the Movement Toward Revolution for the purpose of showing association. Nothing about the book except its title was revealed to the jury during the prosecution’s case-in-chief. It is true that book titles alone can sometimes have a tendency to prejudice a defendant, United States v. McCrea, supra, 583 F.2d at 1086, but in this case the exhibit’s probative value clearly outweighed the title’s slightly prejudicial effect. McCrea is readily distinguishable from the instant appeal because the books which were introduced by the prosecution in McCrea were totally lacking in probative value, either as works of literature containing a particular type of information or as physical objects linking the persons who read them. McCrea involved the prosecution of a single defendant who was charged with possession of unregistered firearms and destructive devices. Knowing possession was all the government had to prove; the defendant’s intent was immaterial. See United States v. Freed, 401 U.S. 601, 607, 91 S.Ct. 1112, 28 L.Ed.2d 356 (1971). One cannot logically infer possession of firearms and explosives (as opposed to knowledge of how to use them) from mere possession of books about guns, bombs, and related subjects. Thus the books’ contents contributed nothing to the truth finding process. The McCrea opinion does not give any indication as to whether the books in question bore the defendant’s or anyone else’s fingerprints. Even if they had, the books still would have been immaterial: since McCrea, unlike the case at bar, was not a conspiracy prosecution, whether the defendant did or did not associate with other persons was completely irrelevant. In contrast to the books at issue in McCrea, From the Movement Toward Revolution had a great deal of probative value. As one of the three pieces of physical evidence corroborating Meyer’s and McSherry’s testimony that Giese associated with the other defendants and the unindicted co-conspirators, thereby affording him an opportunity to enter into an agreement with them, Exhibit C-49 played an important role at trial. Of course, casual association, without more, is not proof of participation in a conspiracy, “but that is not to say that it [is] irrelevant to the issue. ‘[P]roof of * * * association or acquaintance, while not alone enough to establish the conspiracy, yet has sufficient bearing thereon to make it admissible.’ ” Williamson v. United States, 310 F.2d 192, 199 (9th Cir. 1962) quoting Kanner v. United States, 34 F.2d 863, 866 (7th Cir. 1929). See also United States v. Armone, 363 F.2d 385, 403-04 (2d Cir.), cert. denied, 385 U.S. 957, 87 S.Ct. 398, 17 L.Ed.2d 303 (1966) (“Since agreement is an element of conspiracy, evidence of association is relevant.”) Giese contends that even if evidence of association does have probative value under some circumstances, it had no value here because association was never in dispute: “Dr. Giese’s acquaintance with each of the alleged conspirators was conceded; his own direct testimony established that he had a relationship with each of them.” Brief for Appellant at 45. In effect, Giese argues that the propriety of the government’s proof of association, which was presented long before Giese took the stand, should be judged with the hindsight provided by his testimony on direct examination. This proposition is obviously without merit. The prosecution’s evidence is not retroactively rendered inadmissible because it eventually turns out that the defendant chooses not to contest the point. The government had to prove agreement, and thus association, as part of its prima facie case. The fact of association was not stipulated to before trial, so until it heard Giese’s testimony, the government had no way of knowing whether he would admit or deny his fraternization with the other conspirators. Association did not cease to be an issue until after the government had rested; therefore it would be unfair as well as inaccurate to say the prosecution lacked a justification for submitting evidence on the question in its case-in-chief. Although the government’s use of Exhibit C — 49 in its case-in-chief was limited to proving association, the prosecution gained the right to cross-examine Giese on From the Movement Toward Revolution’s contents when, on direct examination, Giese testified about the contents of a number of books and suggested they were indicative of his peaceable character. Giese took the stand in his own behalf and denied supplying his alleged confederates with From the Movement Toward Revolution and the various explosives and firearms manuals which had been found in their possession. R.T. at 1673-76. Had he stopped his testimony about books at that point, he would not have opened any doors. But he did not stop. In response to his counsel’s questions, Giese produced a stack of 18 books and proceeded to describe them one by one. R.T. at 1676-82. All 18 were introduced into evidence later in the trial and were available for the jury’s inspection. R.T. at 1918. Some of the items were “representative samples” of the types of books Giese stocked in his bookstore, R.T. at 1676; others, including three books Giese had written, were his personal property and had been kept at his home rather than at the bookstore. R.T. at 1678, 1734. None of the books had been seized by the government; none had been mentioned during the prosecution’s case-in-chief; none had any connection with the offenses charged in the indictment. Likewise, the books were irrelevant to the issue of association: so far as the record shows, the other conspirators had never even seen the 18 books, let alone shared them with Giese. Giese’s direct examination testimony about the 18 books filled almost six pages of the reporter’s transcript. R.T. at 1676-82. He prefaced his remarks with the statement that he had not “necessarily read all of these books,” R.T. at 1676, but he left no doubt that he had read many of them. For instance, he offered a rather detailed exegesis of Frederick Engels’ Dialectics of Nature; he discussed Camus’s background; and he explained the theses of Pierre Jalle’s Pillage of the Third World and Andre Gorz’s Strategy for Labor, A Radical Proposal. He gave brief descriptions of the contents of Soul On Ice by Eldridge Cleaver, Away With All Pests: An English Surgeon in People’s China, 1954-1969 by Joshua Horn, Capitalism and Underdevelopment in Latin America by Andre Gunder Frank, Soledad Brother by George Jackson, Black Elk Speaks by John G. Neihardt, Viet Nam in Photographs and Text by Felix Greene, Limits to Growth (a report for the Club of Rome), and American Radicals: Some Problems and Personalities. Giese also mentioned Sisterhood Is Powerful, An Anthology of Writings from the Women’s Liberation Movement by Robin Morgan, Readings in U.S. Imperialism by K. T. Fann and Donald C. Hodges, and Monopoly Capital, An Essay on the American Economic and Social Order by Paul A. Baran and Paul M. Sweezy. The three works Giese had written were Artus Desire, Priest and Pamphleteer of the Sixteenth Century, French Lyric Poetry, and an article on Camus and Algeria which was published in the Colorado Quarterly. Giese implied that the 18 books exemplified the kind of literature he sold, owned, or read, and that the literature, in turn, reflected his left-wing but non-revolutionary political views. His testimony about the 18 books, unlike his statements denying that he had sold the books introduced by the prosecution, was more than just an attempt to explain away government exhibits. The books were pieces in the overall mosaic of character evidence which Giese presented on direct examination. He prefaced his testimony about books with a detailed account of his involvement in various political causes, placing special emphasis on his participation in peaceful civil rights and anti-war movements. He described how he had grown increasingly concerned during the 1960s about social conditions and the direction which American foreign policy had taken. At first he had manifested this concern by taking part in marches and sit-ins. Then around 1969 he received a sizeable inheritance and decided that the best way to propagate his political views was to establish the Radical Education Project bookstore. R.T. at 1666-73. By juxtaposing an account of his participation in peaceful demonstrations with an explanation of his reasons for founding the bookstore and a description of the types of books he sold, owned, or read, Giese portrayed himself as a scholarly, humane, peace-loving political activist who possessed a decidedly non-violent character. He told the jurors to look at his track record. In the past, whenever he had wanted to bring about a change in government policy, he had picketed or tried to persuade others by disseminating ideas— the kinds of ideas contained in the 18 books. He suggested that, given this personal history, it would have been inconceivable for him to have turned to violence in order to make a political statement. Michelson v. United States, 335 U.S. 469, 69 S.Ct. 213, 93 L.Ed. 168 (1948), remains the leading case on the use of character evidence by a defendant. There the Court, speaking through Mr. Justice Jackson, said: “Courts' that follow the common-law tradition almost unanimously have come to disallow resort by the prosecution to any kind of evidence of a defendant’s evil character to establish a probability of his guilt. Not that the law invests the defendant with a presumption of good character, Greer v. United States, 245 U.S. 559, 38 S.Ct. 209, 62 L.Ed. 469, but it simply closes the whole matter of character, disposition and reputation on the prosecution’s case-in-chief. The state may not show defendant’s prior trouble with the law, specific criminal acts, or ill name among his neighbors, even though such facts might logically be persuasive that he is by propensity a probable perpetrator of the crime. The inquiry is not rejected because character is irrelevant; on the contrary, it is said to weigh too much with the jury and to so overpersuade them as to prejudge one with a bad general record and deny him a fair opportunity to defend against a particular charge. The overriding policy of excluding such evidence, despite its admitted probative value, is the practical experience that its disallowance tends to prevent confusion of issues, unfair surprise and undue prejudice. “But this line of inquiry firmly denied to the State is opened to the defendant because character is relevant in resolving probabilities of guilt. He may introduce affirmative testimony that the general estimate of his character is so favorable that the jury may infer that he would not be likely to commit the offense charged. “The price a defendant must pay for attempting to prove his good name is to throw open the entire subject which the law has kept closed for his benefit and to make himself vulnerable where the law otherwise shields him.” 335 U.S. at 475-76, 479, 69 S.Ct. at 218-220. Giese threw open the subject of his literary tastes and reading habits when he testified about the specific acts of selling, reading, and owning the 18 books. Unlike character witnesses, who must restrict their direct testimony to appraisals of the defendant’s reputation, a defendant-witness may cite specific instances of conduct as proof that he possesses a relevant character trait such as peaceableness. And “[o]nce a witness (especially a defendant-witness) testifies as to any specific fact on direct testimony, the trial judge has broad discretion to admit extrinsic evidence tending to contradict the specific statement, even if such statement concerns a collateral matter in the case.” United States v. Benedetto, 571 F.2d 1246, 1250 (2d Cir. 1978). Professor McCormick’s treatise states that where the defendant implicitly invites the jury to infer something about his character from his description of his background and conduct, he opens the door to cross-examination on all reasonably related matters: “Ordinarily, when courts speak of an accused’s putting his character in issue, it is assumed that the means by which he does so is introducing witnesses who testify to his good character in terms of reputation, or, more currently, opinion. Note should be taken, however, that by relating a personal history supportive of good character, a defendant may be opening the door to rebuttal evidence along the same line.” McCormick’s Handbook of the Law of Evidence § 191, at 59 (2d ed. Supp. Cleary et al. 1978). Because character testimony alone may be enough to raise a reasonable doubt, defendants traditionally have been afforded considerable latitude when they testify about their personal histories. Sometimes they commit tactical blunders. We are cognizant of the limitations inherent in the use of literature as proof of character, and we do not applaud the strategy employed by Giese and his attorney. Nor do we bestow our imprimatur on the concept of trial by books. Nevertheless, the question before this court is not whether we think books are a persuasive form of character evidence; the issue is whether the government had a right to respond once the defendant had, of his own volition, chosen that method of proving he was a peaceable, law-abiding individual. It is well-settled that the admissibility of character evidence “depend[s] on numerous and subtle considerations difficult to detect or appraise from a cold record, and therefore rarely and only on clear showing of prejudicial abuse of discretion will Courts of Appeals disturb rulings of trial courts on this subject.” Michelson v. United States, supra, 335 U.S. at 480, 69 S.Ct. at 221. Moreover, a trial judge has considerable discretion in determining what lines of cross-examination are reasonably related to the subject matter of the witness’ direct testimony. United States v. Higginbotham, 539 F.2d 17, 24 (9th Cir. 1976); United States v. Palmer, 536 F.2d 1278, 1282 (9th Cir. 1976). The judge’s ruling on the scope of proper cross-examination should not be interfered with on appeal unless he has plainly abused his discretion. Lewis v. United States, 373 F.2d 576, 578 (9th Cir.), cert. denied, 389 U.S. 880, 88 S.Ct. 116, 19 L.Ed.2d 173 (1967). Justice would not have been served had the jurors been left with only the one-sided impressions created by Giese’s 18 innocuous books. To show the opposite side of the coin, as it were, it was fair for the government to cross-examine Giese on other books he had sold, owned, or read. From the Movement Toward Revolution was such a book. It is true that Giese did not keep From the Movement Toward Revolution in stock at the bookstore, but he did not sell all of the 18 books there either. However, there is no doubt that Giese read and owned From the Movement Toward Revolution. In addition to handling and perhaps reading Severin’s copy of the book, Giese possessed his own copy, portions of which he had read. Given Giese’s fairly extensive contacts with the book, we hold that the court below did not abuse its discretion in permitting the prosecution to inquire about From the Movement Toward Revolution on cross-examination. The court also correctly overruled Giese’s objections that the book’s contents were irrelevant and hearsay. From the Movement Toward Revolution was relevant for the dual rebuttal purposes of contradicting Giese’s character evidence and impeaching his veracity as a witness. The passages he was asked to read were not hearsay because they were not introduced to prove the truth of the matter asserted (i. e., that violent revolution is a desirable way to bring about social and political change.) Giese claims the prosecutor “forced” him to read in front of the jury, an act he says unfairly prejudiced him. The record shows, however, that Giese was not forced to do anything. He did not protest when the assistant U. S. attorney asked him to read a particular passage. Neither his lawyer nor any other defense attorney objected to the act of reading as such. Giese was no more “forced” to read from the book than is a witness who is asked to read a prior inconsistent statement to the jury. If the witness demonstrates an unwillingness to do the reading — and no such unwillingness was shown here — the prosecutor can simply read the document to the jury himself. The trial judge is accorded considerable discretion in deciding how evidence should be presented, just as he is given substantial discretion in determining what evidence should be received. In both instances, he must balance probative value on the one hand and degree of prejudice on the other. United States v. Robinson, 560 F.2d 507, 515 (2d Cir. 1977) (en banc), cert. denied, 435 U.S. 905, 98 S.Ct. 1451, 55 L.Ed.2d 496 (1978), held that “the preferable rule” in reviewing a district court’s decision on the question of unfair prejudice “is to uphold the trial judge’s exercise of discretion unless he acts arbitrarily or irrationally.” The reason for granting such broad discretion to the trial judge is that “he is in a superior position to evaluate the impact of the evidence, since he sees the witnesses, defendants, jurors, and counsel, and their mannerisms and reactions. [Citation omitted.] He is therefore able, on the basis of personal observation, to evaluate the impressions made by witnesses, whereas we [appellate judges] must deal with the cold record.” Id. at 514. United States v. Doremus, 414 F.2d 252 (6th Cir. 1969), sets forth a useful test for determining whether requiring a defendant to perform a given act on the witness stand unjustly prejudices him. Impermissible prejudice results when “the requested performance or demonstration would unjustly humiliate or degrade the defendant” or “such performance would be damaging to the defendant’s image and irrelevant to the issue on trial.” 414 F.2d at 254. Giese suffered no such injuries. Whereas some acts — such as a forced reenactment of an especially shocking crime — might degrade a defendant beyond repair, in this case Giese’s attorney could easily have mitigated whatever damage resulted from the act of reading by simply asking his client on re-direct whether he agreed with what the book said. For reasons which are not apparent in the record, no such rehabilitative effort was made. But in any event, the act of reading probably did not significantly injure Giese’s defense. In some ways, having Giese read the passage was actually less prejudicial than having the prosecutor or a witness do it. Giese was free to read in whatever tone he pleased. He could emphasize some words and skim over others. Had he read the excerpt, the prosecutor might have stressed its more violent parts, whereas Giese was able to read it in a monotone if he wished. By reading the extract himself, Giese could and did express unfamiliarity with the ideas contained therein. After reading a few lines, he paused and said “I am trying to make sense out of that sentence.” R.T. at 1768. See note 26 supra. In so doing, he suggested that he had not absorbed and adopted the revolutionary arguments set forth in the book. Allowing Giese to choose the tone in which the contents of From the Movement Toward Revolution were communicated to the jury could only have diminished, not i