Full opinion text
CHARLES CLARK, Circuit Judge: This appeal presents important questions concerning the scope of relief available under 42 U.S.C. § 1985(3), the extent of congressional power to enact a civil remedy for wholly private infringement of constitutional rights, and the relationship between section 1985(3) and the labor relations laws. The district court issued a permanent injunction against the defendants, including numerous labor organizations. It also awarded money damages for violations of section 1985(3), concluding that the statute afforded a remedy for the kind of private conspiracy involved here and that Congress was constitutionally empowered to provide such a remedy. For the reasons stated below, we affirm in part and reverse in part. I. THE FACTUAL BACKGROUND This case arises out of an episode of mob violence that occurred in the early morning hours of January 17, 1975. The plaintiffs are A. A. Cross Construction Company, Inc., and two of its employees, Paul Scott and James Matthews. The defendants include the Sabine Area Building and Construction Trades Council, a loose confederation of craft and construction unions located in the Port Arthur, Texas, area. Also named as defendants are twenty-five of the Council’s member unions and several individual members of some of these labor unions. The individual defendants are not parties to this appeal. The plaintiffs contend that the defendants conspired for the purpose of depriving them of the equal protection of the laws and equal privileges and immunities under the law when they planned and executed an attack on the Cross construction site, assaulting workers and destroying property. A. A. Cross Construction Company is a Texas corporation engaged in the building and construction industry as a general contractor. In May, 1974, Cross contracted with the Department of the Army, United States Corps of Engineers to erect the Alligator Bayou Pumping Station and Gravity Drainage Structure on the hurricane levee along Taylor’s Bayou near Port Arthur. The agreement had a contract price in excess of $8 million and called for the construction of the pump station with four pumps and a gravity drain for flood control. In accordance with its customary practice, the Cross Construction Company hired its workers for the Alligator Bayou project without regard to union affiliation, employing persons solely on the basis of its own need for the applicant’s occupational skills. Cross did not have a collective bargaining agreement with any labor union, and when this incident occurred no union was seeking to organize the company’s employees. In addition, Cross often hired workers from outside the Port Arthur community. Cross Construction Company’s hiring practices provoked an antipathetic response from some segments of the Port Arthur community. In fact, on several occasions prior to the eruption of violence on January 17, popular enmity had risen to the level of warnings and threats directed against Cross and its employees. Local residents had confronted Cross employees at a local tavern and pool hall frequented by them, threatening to place pickets at the construction site, promising to make Cross “go union,” and occasionally warning of trouble if Cross did not cease hiring nonunion laborers. About three months before the January 17 attack, one of the individual defendants, Bill Moore, approached Mr. Cross and threatened that he would “hurt you bad,” saying, “What is going to happen when that big rig of yours down there burns up?” On another occasion, John Wallace, financial secretary and business representative for the Carpenters Local 610, had told Cross that “this is union country” and that if he persisted in using nonunion labor it was “going to cost you a million dollars.” Meanwhile, during the months preceding the January 17 violence, rumors began to develop concerning a “citizens protest” to be staged at the Alligator Bayou construction site. These rumors contemplated a public demonstration to call attention to the fact that Cross hired nonunion labor and did not have a labor contract with any union as well as to protest the company’s policy of hiring employees from outside the Port Arthur community. There is no direct evidence to show the organizing force behind this protest demonstration, but on Wednesday, January 15, two days before the assault on the Cross jobsite, the Sabine Area Building Trades Council held its regular weekly meeting. Cross Construction Company’s indifference to prospective employees’ union status and its lack of a union contract had long been topics of concern at the Council’s meetings, and they were once again discussed during the January 15 session. In addition, the group discussed the rumored citizens protest, and some of the union representatives in attendance informed the Council that the demonstration had apparently been scheduled for the following Friday. On Thursday, the sixteenth, Cross Construction Company learned of the scheduled protest from two union employees associated with the Alligator Bayou project. Fred Dukes, a member of Cement Masons Local 884, worked for Cross as a cement finisher on a two-day job. Earl Stevens, a member of Plumbers Local 504, worked as a foreman for Cross Construction Company’s mechanical subcontractor. Both men received warnings from their respective union business agents about a possible picket or demonstration to be held at the Cross construction site, and both men passed that information along to Cross. Neither Dukes nor Stevens had heard anything about violent or destructive conduct. Nevertheless, Cross directed its employees to report for work at 6:00 a. m. on Friday, an hour earlier than usual, in order to avoid any confrontation between them and the demonstrators. On the morning of January 17, after most of the Cross employees had arrived at work, a crowd of nearly three hundred people assembled at the main access road leading to the Cross construction site. Several vehicles made brief forays up the access road, and their occupants confirmed with Cross and Scott that they were at the Cross Construction Company jobsite. The crowd began to get unruly, pushing and shoving the remaining Cross workers as they arrived. Nevertheless, Cross’s employees began work as usual. Then, shortly after 7:00 that morning, a group of four pickup trucks, each carrying between twelve and eighteen persons, emerged from the crowd gathered at the access road and drove onto the job-site. Plaintiff Scott went out to meet the intruders and to request them to leave the area, but one of them approached Scott and said, “Man, you all have got to be crazy ... this is a union town.” Scott told his interlocutor that they did not want any trouble, and he attempted to gather together the other employees and to leave the jobsite. However, before he could complete his mission, someone stepped out of the group and struck him on the head. Suddenly, the mob swarmed over the construction site, brutally beating Cross and his employees with iron rods and wooden boards, overturning and setting fire to the trailer that served as the construction site office, smashing automobile and truck windshields, and vandalizing company tools and equipment. The entire episode lasted only a few minutes, but the destruction was devastating. Cross and his employees were treated for their injuries at a local hospital, and work at the construction site did not resume for nearly three weeks. Some of Cross’s employees, frightened by the possibility of repeated attacks at the jobsite, refused to return to work. In addition, the violence and vandalism delayed the completion of the project by about six months, ultimately causing the Cross Construction Company to default in its contractual obligation to the U. S. Army Corps of Engineers. On January 31, 1975, plaintiffs Scott and Matthews initiated this lawsuit against the individual defendants. They sought and obtained a temporary injunction retraining the then-named defendants and “all persons, firms, and associations combining or conspiring with defendants” from further violent, intimidating, or destructive acts against employees at the Alligator Bayou Pump Station project. Nearly two years later, the plaintiffs amended their complaint, adding A. A. Cross Construction Company, Inc., as plaintiff and the Sabine Area Building and Construction Trades Council along with twenty-five local unions as defendants. The district court found that the plaintiffs had proved a conspiracy to deprive them of the equal protection of the laws, permanently enjoined the building trades council and twenty-four of the unions from future misconduct, and assessed damages against eleven of the union defendants. II. THE JURISDICTIONAL QUESTION: INJUNCTIVE RELIEF AND THE NORRIS-LAGUARDIA ACT The district court issued a permanent injunction against the Sabine Area Building and Construction Trades Council, twenty-four of its member unions, and all persons conspiring with them. The court’s injunction ordered that those parties subject to its terms .. . shall not hereafter combine, conspire, threaten, intimidate, assault, or commit any act of violence toward or upon any person, property or possession of any person or his family who may work upon, travel to, deliver materials, goods, or services to A. A. Cross Construction Co., Inc., or to the site of the alligator Bayou Pump Station on Taylor’s Bayou near Port Arthur, Jefferson County, Texas. The defendants contest the district court’s power to issue such an injunction, arguing that the Norris-LaGuardia Act deprives the district court of jurisdiction to enjoin labor organizations from engaging in conspiratorial conduct. They maintain that the unembellished language of the Act is sufficient to show the court’s usurpation of authority. We disagree. The Norris-LaGuardia Act was passed for the purpose of limiting the circumstances and conditions under which injunctive action could be taken against labor organizations in the context of a labor dispute. The labor injunction had been an important device used by employers to counter organized labor’s most effective economic weapons, strikes, boycotts, and picket lines. However, the Act was predicated on the conviction that labor disputes turned on issues of social and economic policy that could not appropriately be resolved by the courts. The legislative solution to the problems confronting workers in a complex industrial economy was union organization and collective bargaining. Since the ready issuance of labor injunctions presented a serious obstacle to the concerted activities of organized workers, Congress decided to remove the federal judiciary from labor disputes. Thus, section 5 of the Act, 29 U.S.C. § 105, limits the equitable power of the federal courts in the following way: No court of the United States shall have jurisdiction to issue a restraining order or temporary or permanent injunction upon the ground that any of the persons participating or interested in a labor dispute constitute or are engaged in an unlawful combination or conspiracy because of the doing in concert of the acts enumerated in section 104 of this title. 29 U.S.C. § 105. But the Act does not impose an unqualified prohibition against federal injunctive relief. Section 105 merely restricts the court’s power to enjoin concerted or conspiratorial activity where the conduct to be enjoined is an act enumerated in section 104. The enumerated acts include refusing to work, joining a labor organization, paying or withholding strike benefits from a labor disputant, lawfully giving aid to a labor disputant who is prosecuting or defending a court action, truthfully and peacefully publicizing a labor dispute, peacefully assembling to promote one’s interests in a labor dispute, and agreeing with or inducing other persons to do any of those acts. In short, section 104 interdicts injunctive relief against the legitimate activities of labor unions. However, there is nothing in this provision denying to federal courts the power to enjoin violence, breaches of the peace, or criminal acts simply because they may be committed by persons participating or interested in a labor dispute. In fact, the Norris-LaGuardia Act itself implicitly recognizes the threatened commission of violent acts as a condition under which an injunction may issue. Section 107 states that no court of the United States has jurisdiction to grant an injunction, unless, after a hearing, the court finds “[t]hat unlawful acts have been threatened and will be committed unless restrained .... ” 29 U.S.C. § 107(a). Thus, violence, intimidation, threats, vandalism and combinations or conspiracies to commit such acts may be restrained and enjoined even though they arise in connection with a labor dispute. See, e. g., Westinghouse Broadcasting Co. v. Dukakis, 412 F.Supp. 580 (D.Mass.1976); Potomac Electric Power Co. v. Congress of Racial Equality, 209 F.Supp. 599 (D.D.C.1962). The Norris-LaGuardia Act does not divest the district court of jurisdiction to enjoin the kind of violent conduct present in this case. III. THE STATUTORY QUESTION: THE SCOPE OF REMEDY UNDER 42 U.S.C. § 1985(3) A. Griffin v. Breckenridge Section 1985(3) was originally enacted by Congress as a part of the Ku Klux Klan Act in order to enforce the Civil War amendments to the Constitution and to provide a means of redress for persons victimized by the Elan’s acts of terror and intimidation. The statute imposes civil liability on persons conspiring to deprive another person or class of persons of “the equal protection of the laws, or of equal privileges and immunities under the laws.” Narrow judicial construction made section 1985(3) a seldom-used remedy during the first century after its enactment. See, e. g., Collins v. Hardyman, 341 U.S. 651, 71 S.Ct. 937, 95 L.Ed. 1253 (1951). However, the Supreme Court decided in 1971 to “accord to the words of the statute their apparent meaning” and held section 1985(3) provided a civil remedy for damages against wholly private infringements of constitutionally protected rights. Griffin v. Breckenridge, 403 U.S. 88, 97, 91 S.Ct. 1790, 1795, 29 L.Ed.2d 338, 345 (1971). In Griffin, a group of whites assaulted three black men along a Mississippi highway in the mistaken belief that their victims were the associates of a civil rights worker. The blacks brought an action under section 1985(3) to redress violations of the laws of the United States and of Mississippi, including the rights of free speech, assembly, association, interstate travel, liberty, and security of their persons. The Supreme Court first held that the text of the statute, recent judicial interpretations given to related civil rights provisions, the complementary relationship of the various civil rights statutes, and the legislative history surrounding section 1985(3) all “point unwaveringly to § 1985(3)’s coverage of private conspiracies.” 403 U.S. at 101, 91 S.Ct. at 1798, 29 L.Ed.2d at 347. While eliminating the state action requirement, the Griffin court was concerned that the statute, if applied too broadly, would displace many areas of tort law that have traditionally been reserved to the states and thereby violate constitutionally-based principles of federalism. “That the Statute was meant to reach private activity does not ... mean that it was intended to apply to all tortious, conspiratorial interferences with the rights of others.” 403 U.S. at 101, 91 S.Ct. at 1798, 29 L.Ed.2d at 347. Accordingly, the Court read section 1985(3) to apply only to actions which are inspired by “some racial, or perhaps otherwise class-based, invidiously discriminatory animus.” 403 U.S. at 102, 91 S.Ct. at 1798, 29 L.Ed.2d at 348. It then delineated four elements necessary for a plaintiff to establish a § 1985(3) cause of action: (1) the defendants must conspire or go in disguise on the highway or premises of another; (2) for the purpose of depriving, either directly or indirectly, any person or class of persons of the equal protection of the laws, or of equal privileges and immunities under the laws; and (3) one or more of the conspirators must commit some act in furtherance of the conspiracy; whereby (4) another is either (a) injured in his person or property or (b) deprived of having and exercising any right or privilege of a citizen of the United States. See id. at 102-03, 91 S.Ct. at 1790, 29 L.Ed.2d at 348. Subsequently, this court has added a fifth element, (5) that the conspirators’ conduct must be unlawful independent of the section 1985(3) violation. See McLellan v. Mississippi Power & Light Co., 545 F.2d 919 (5th Cir. 1977) (en banc). The Griffin court, having concluded that the plaintiffs had stated a cause of action under section 1985(3), then sought to locate a source of congressional power to reach the private conspiracy alleged. The sources identified in Griffin were the Thirteenth Amendment and the constitutional right to travel. 403 U.S. at 104-06, 91 S.Ct. at 1799-1800, 29 L.Ed.2d at 349-50. The Court observed, however, that other provisions of the Constitution, including section 5 of the Fourteenth Amendment, might empower Congress to reach other conspiracies by private persons. Id. at 107, 91 S.Ct. at 1801, 29 L.Ed.2d at 351. However, the Court found the facts of that case made it unnecessary to look beyond the Thirteenth Amendment and the right to interstate travel. B. The Present Case Griffin’s principles indicate the plaintiffs here have made out a cause of action under section 1985(3). The facts of this case clearly embody four of the five elements essential to a successful § 1985(3) claim. First, the evidence is sufficient to establish a conspiracy among some of the Council’s constituent unions and individual defendants. Second, proof that plaintiffs were assaulted, beaten, and threatened and that property was destroyed establishes the requisite “act in furtherance” of the conspiracy. Third, these acts are indisputably illegal apart from § 1985(3) as required by McLellan. Fourth, there is evidence of personal injuries, property damage, and economic loss. The only element requiring analysis is the requirement that the conspiracy be for the purpose of depriving a person of the equal protection of the laws or equal privileges and immunities under the laws. This requirement, in turn, has two components: (1) the violation of some protected right and (2) a class-based, invidiously discriminatory animus motivating the violation. 1. Violation of a Protected Right In Griffin, the Supreme Court stated that a § 1985(3) conspiracy “must aim at a deprivation of the equal enjoyment of rights secured by the law to all.” 403 U.S. at 102, 91 S.Ct. at 1798, 29 L.Ed.2d at 348. The plaintiffs in the case at bar contend that the object of the defendants’ conspiracy was to deprive them of their First Amendment right to associate with their fellow nonunion employees. They argue that curtailment of their interests secured by the First Amendment is a deprivation of equal protection of the laws within the meaning of section 1985(3) as interpreted by Griffin. The Ku Klux Klan Act was originally entitled, “An Act to Enforce the Provisions of the Fourteenth Amendment to the Constitution of the United States, and for Other Purposes.” 17 Stat. 13 (1871). The guaranties afforded by the First Amendment are protected by the due process clause of the Fourteenth Amendment. E. g., Williams v. Rhodes, 393 U.S. 23, 30-31, 98 S.Ct. 5, 10, 21 L.Ed.2d 24, 31 (1968); New York Times v. Sullivan, 376 U.S. 254, 276-77, 84 S.Ct. 710, 724, 11 L.Ed.2d 686, 704 (1964); Cantwell v. Connecticut, 310 U.S. 296, 303, 60 S.Ct. 900, 903, 84 L.Ed. 1213, 1217 (1940); De Jonge v. Oregon, 299 U.S. 353, 364, 57 S.Ct. 255, 260,81 L.Ed. 278, 283 (1937). Moreover, the right of free association is closely aligned with the right of free speech and is similarly protected by the First Amendment. E. g., Abood v. Detroit Board of Education, 431 U.S. 209, 233, 97 S.Ct. 1782, 1798-99, 52 L.Ed.2d 261, 283 (1977); Healy v. James, 408 U.S. 169, 181, 92 S.Ct. 2338, 2346, 33 L.Ed.2d 266, 279 (1972); Baird v. State Bar of Arizona, 401 U.S. 1, 6, 91 S.Ct. 702, 705, 27 L.Ed.2d 639, 646 (1971); NAACP v. Alabama ex rel. Patterson, 357 U.S. 449, 462, 78 S.Ct. 1163, 1171-72, 2 L.Ed.2d 1488, 1499 (1958). The defendants urge that section 1985(3) does not provide a remedy for private interference with First Amendment freedoms. They appeal to the well-established principle that the Fourteenth Amendment “erects no shield against merely private conduct, however discriminating or wrongful.” Shelley v. Kraemer, 334 U.S. 1, 13, 68 S.Ct. 836, 842, 92 L.Ed. 1161, 1180 (1948). To support their construction of section 1985(3), the defendants rely upon several decisions of the Seventh Circuit. In Dombrowski v. Dowling, 459 F.2d 190 (7th Cir. 1972), the court held that section 1985(3) does not afford protection against private deprivations of rights protected under the Fourteenth Amendment absent some kind of state involvement. Emphasizing the historical connection between sections 1983 and 1985(3), the court decided that it is necessary to identify the interests which Congress intended to protect from unequal treatment as well as the kinds of conduct which it meant to proscribe. The breadth of the statute’s coverage is yet to be determined, but three categories of protected rights have been plainly identified. Griffin gives express recognition to a black citizen’s Thirteenth Amendment rights and to his federal right to travel interstate; the title of the statute expressly identifies the third category, namely, rights protected by the Fourteenth Amendment. We think the § 1983 eases make it clear that in this third category a “state involvement” requirement must survive Griffin. 459 F.2d at 195 (footnotes omitted). Subsequently the Seventh Circuit has extended the Dombrowski rationale in Murphy v. Mount Carmel High School, 543 F.2d 1189 (7th Cir. 1976), expressly holding that section 1985(3) provides no remedy for purely private impairment of First Amendment speech and associational freedoms. Accord Bellamy v. Mason’s Stores, Inc., 508 F.2d 504 (4th Cir. 1974). The Seventh Circuit’s reasoning is contrary to the Supreme Court’s analysis in Griffin. Of course, most basic constitutional provisions impose limitations on the power of government to regulate private conduct. Thus, the rights they confer on individuals are typically rights of the individual against the state. But the Griffin court, after acknowledging the conceptual difficulties associated with private deprivations of constitutional rights, construed section 1985(3) to reach both public and private constitutional wrongs. A century of Fourteenth Amendment adjudication has .. . made it understandably difficult to conceive what might constitute a deprivation of the equal protection of the laws by private persons. Yet there is nothing inherent in the phrase that requires the action working the deprivation to come from the State. Indeed, the failure to mention any such requisite can be viewed as an important indication of congressional intent to speak in § 1985(3) of all deprivations of “equal protection of the laws” and “equal privileges and immunities under the laws,” whatever their source. 403 U.S. at 97, 91 S.Ct. at 1796, 29 L.Ed.2d at 345 (citation omitted and some emphasis supplied). Thus, Griffin made it unmistakably clear that section 1985(3) was intended to provide a remedy for all private conspiracies. “It is thus evident that all indicators text, companion provisions, and legislative history—point unwaveringly to § 1985(3)’s coverage of private conspiracies.” Id. at 101, 91 S.Ct. at 1798, 29 L.Ed.2d at 347. The Griffin Court’s method of analysis and the unequivocal language of its opinion foreclose our adoption of the approach taken by the Seventh Circuit. In addition, the interpretation given to the statute in this circuit makes that approach unnecessary. Although Griffin found that section 1985(3) covered purely private conspiracies, it did not announce what might constitute a deprivation of equal protection by private persons. Uncertainty in this regard may have contributed to the Seventh Circuit’s decision to retain some form of state involvement as a part of the § 1985(3) cause of action. See Dombrowski, 459 F.2d at 194. However, this circuit has adopted a different tack. McLeilan establishes that section 1985(3) was not intended to redress every conceivable private interference with another’s rights. Rather, “the object of a section 1985(3) conspiracy must be to deprive another of the enjoyment of legal rights by independently unlawful conduct.” McLeilan, 545 F.2d at 927 (footnote omitted). The independent illegality requirement was derived in part from the passage in United States v. Harris, 106 U.S. 629, 1 S.Ct. 601, 27 L.Ed. 290 (1883), which explains that the only method by which a “private person can deprive another of the equal protection of the laws is by the commission of some offense against the laws which protect the rights of persons, as by theft, burglary, arson, libel, assault, or murder.” Id. at 643, 1 S.Ct. at 612, 27 L.Ed. at 295. In this way, McLeilan limited the potentially boundless reach of the statute and provided meaning to the concept of a private impairment of constitutional rights. Therefore, McLeilan resolved the difficulties perceived by the Dombrowski court and made its analysis unnecessary. It cannot be gainsaid that the defendants’ conspiracy comprehended an intent to violate the law independent of section 1985(3). The plaintiffs contend that the conspiracy was calculated to deprive them of the right to freely associate with other nonunion laborers. They have alleged and have sought to prove that the defendants conspired to accomplish this object by assaulting and beating them with wooden boards and iron bars; by destroying tools, equipment, and automobiles; and by overturning and setting fire to the Cross office trailer. The means adopted by the conspirators to deprive the plaintiffs of their rights of free association encompass patent violations of both the civil and criminal laws of Texas. See, e. g., Tex.Penal Code Ann. §§ 22.01 (assault); 22.02 (aggravated assault); 28.02 (arson); 28.04 (reckless damage or destruction) (Vernon 1974). See generally W. Prosser, Law of Torts §§ 9-10 (assault and battery); 14 (trespass to chattels). The plaintiffs also offered proof that the conspirators engaged in the very unlawful conduct they conspired to commit and that as a result plaintiffs suffered injury to their persons and property. Under such circumstances, we conclude that section 1985(3) affords a remedy for purely private conspiracies aimed at denying their victims the First Amendment right of free association. 2. Discriminatory, Class-Based Animus The plaintiffs have also satisfied Griffin’s class-based, discriminatory animus component of the § 1985(3) cause of action. Our analysis involves two distinct but closely related questions. First, does section 1985(3) coverage extend to private conspiracies founded upon some invidiously discriminatory animus other than racial prejudice? Second, if it does, is the particular class to which the plaintiffs belong, nonunion workers and their employers, one which falls within the statute’s protective ambit? We answer both these questions in the affirmative. There is no allegation that the defendants in this case were motivated by an invidiously discriminatory racial animus, and there is no evidence that would support such an allegation. Indeed, the theory of the plaintiffs’ case is that they are the victims of a conspiracy motivated by the defendants’ hostility toward nonunion workers of any race and the employers who hire them. We must, therefore, answer the question specifically reserved by Griffin and still unanswered in this circuit: does section 1985(3) reach conspiracies founded upon discriminatory animus directed against classes defined by some characteristic other than race? Griffin noted that not all private conspiracies to interfere with the rights of another would come under the protective umbrella of section 1985(3). The Court determined the congressional purpose was to include only those conspiracies animated by an “invidiously discriminatory motivation.” The language requiring intent to deprive of equal protection, or equal privileges and immunities, means that there must be some racial, or perhaps otherwise class-based, invidiously, discriminatory animus behind the conspirators’ action. 403 U.S. at 102, 91 S.Ct. at 1798, 29 L.Ed.2d at 348 (some emphasis supplied). Thus, Griffin expressly left open the possibility that a § 1985(3) cause of action existed against private conspiracies inspired by some nonracial class bias. Encouraged by this suggestion, numerous lower courts have already found that section 1985(3) is not limited to protecting classes defined by race. Indeed, we are aware of no post-Griffin decision by a circuit court that has limited the scope of the statute to racially-motivated conspiracies. See cases cited infra at p. 723. Furthermore, extending section 1985(3) protection to include conspiracies motivated by nonracial class animus comports favorably with the Supreme Court’s approach to other Reconstruction civil rights statutes in recent years “to ‘accord [them] a sweep as broad as [their] language.’ ” Griffin v. Breckenridge, 403 U.S. at 97, 91 S.Ct. at 1796, 29 L.Ed.2d at 345. The expansive language of the statute could reach all conspiracies which deprive any class of persons of equal protection of the laws, not just those animated by racial discrimination. Sections 1981 and 1982, for example, both contain specific references to race, and the courts have consistently limited their application to instances of racial discrimination. See, e. g., McDonald v. Santa Fe Trail Transp. Co., 427 U.S. 273, 96 S.Ct. 2574, 49 L.Ed.2d 493 (1976) (§ 1981); Jones v. Alfred H. Mayer Co., 392 U.S. 409, 88 S.Ct. 2186, 20 L.Ed.2d 1189 (1968) (§ 1982); Olivares v. Martin, 555 F.2d 1192 (5th Cir. 1977) (§ 1981). By contrast, however, section 1983 makes no specific reference to race, and a wide variety of nonracial classes have sought and won relief from discriminatory treatment under section 1983. See, e. g., Estelle v. Gamble, 429 U.S. 97, 97 S.Ct. 285, 50 L.Ed.2d 251 (1976) (prisoners); Johnson v. American Credit Co., 581 F.2d 526 (5th Cir. 1978) (debtors attacking state pre-judgment attachment procedure); Morris v. Michigan State Bd. of Education, 472 F.2d 1207 (6th Cir. 1973) (sex). Since section 1985(3), like section 1983, is not cast in racial terms, consistency demands that section 1985(3) also be read to protect nonracial classes. The conclusion that section 1985(3) is not restricted to protecting victims of racial discrimination is also fully supported by the legislative history surrounding the statute’s enactment. Both the congressional debates and the original statute’s popular title suggest that the protection of groups who were being terrorized by the Ku Klux Klan (blacks and white Union sympathizers) was the Act’s primary objective. Although concern for those persons victimized by Klan violence was the most pressing matter leading to adoption of the Act, both proponents and opponents of the legislation understood that it would cover other groups as well. Representative Hoar described the purpose of section 1985(3) as guaranteeing “that under no temptation of party spirit, under no political excitement, under no jealousy of race or caste, will the majority either in numbers or strength in any State seek to deprive the remainder of the population of their civil rights.” Cong. Globe, 42d Cong., 1st Sess. 335 (1871). Senator Edmunds’ famous remarks also aptly illustrate the congressional attitude toward what classes would enjoy section 1985(3)’s protection: We do not undertake in this bill to interfere with what might be called a private conspiracy growing out of a neighborhood feud of one man or set of men against another to prevent one [from] getting an indictment in the State courts against men for burning down his barn; but, if in a case like this, it should appear that this conspiracy was formed against this man because he was a Democrat, if you please, or because he was a Catholic, or because he was a Methodist, or because he was a Vermonter ... then this section could reach it. Cong. Globe, 42d Cong., 1st Sess. 567 (1871). The congressional debates, which reflect a concern for all groups subjected to the Elan’s organized lawlessness, make it appear that the statute’s drafters intended to protect groups other than southern blacks. Griffin, the statutory text, companion civil rights provisions, and the legislative history all indicate that a conspiracy motivated by invidiously discriminatory intent other than racial bias is actionable under section 1985(3). However, the conclusion that section 1985(3) protects nonracial classes resolves only a part of the problem presented by this case, for we must also determine whether the particular class involved here is one which is covered by the statute’s protective cloak. Precisely what kinds of nonracial classes enjoy section 1985(3)’s protection is far from clear. Griffin presented conduct “so close to the core of the coverage intended by Congress that it is hard to conceive of wholly private conduct that would come within the statute” if it did not. 403 U.S. at 103, 91 S.Ct. at 1799, 29 L.Ed.2d at 348. At the same time, the Court’s expressed concern over the broad reach of the statute’s literal language dictates the exercise of restraint in defining what nonracial class-based discrimination is covered. Thus, we expressly limit our holding to a determination that section 1985(3) encompasses a private conspiracy against nonunion laborers and their employer. Appropriate development of judicial precedent demands that further delineation of the statute’s outer limits must await specific cases. Not every conceivable class of persons is covered by the statute. Members of the plaintiff class must share some common characteristic beyond simply being victims of the defendant’s conspiratorial conduct. See, e. g., Askew v. Bloemker, 548 F.2d 673 (7th Cir. 1976) (homeowners raided by drug enforcement agents); Harrison v. Brooks, 519 F.2d 1358 (1st Cir. 1975) (property owners allegedly injured by city council rezoning efforts). The class cannot be so large and amorphous that its members are virtually indistinguishable from the vast majority of the populace. See, e. g., Blevins v. Ford, 572 F.2d 1336 (9th Cir. 1978) (nonlawyers). Even some clearly defined and easily identifiable groups have been denied protected status under the statute. See, e. g., DeSantis v. Pacific Tel. & Tel. Co., 608 F.2d 327 (9th Cir. 1979) (homosexuals); Carchman v. Korman Corp., 594 F.2d 354 (3d Cir. 1979), cert. denied, 444 U.S. 898, 100 S.Ct. 205, 62 L.Ed.2d 133 (1979) (tenant organizers); Lessman v. McCormick, 591 F.2d 605 (10th Cir. 1979) (debtors); McLellan v. Mississippi Power & Light Co., 545 F.2d 919 (5th Cir. 1977) (en banc) (persons who file voluntary bankruptcy petitions); Bricker v. Crane, 468 F.2d 1228 (1st Cir. 1972), cert. denied, 410 U.S. 930, 93 S.Ct. 1368, 35 L.Ed.2d 592 (1973) (physicians who testify in malpractice suits). In the absence of Supreme Court guidance as to the kinds of classes protected by section 1985(3) or a method by which protected classes should be identified, our own en banc decision in McLellan provides our gauge. In McLellan, we held that the statute does not cover persons who file voluntary petitions in bankruptcy. The decision was based on three factors. First, the legislative history of the Eu Elux Elan Act contains no evidence of congressional concern about discrimination against persons who become insolvent. Second, while the protection afforded by the civil rights acts is not static, it would be inappropriate to enlarge the group of protected classes to include bankrupts when Congress had specifically declined to prohibit discrimination against them. Third, including bankrupts within the ambit of section 1985(3) would be unwarranted in light of the Supreme Court’s refusal to characterize the right to file a bankruptcy petition as a fundamental right. 545 F.2d at 932-33. Applying the McLellan factors to our case today, we find that the plaintiffs constitute a class for § 1985(3) purposes. The labor union movement in America was yet to be born when the 42d Congress was in session, so it could not have been specifically concerned with discrimination perpetrated against nonunion laborers. However, the congressional debates evince a hearty regard for persons who are victimized because of their political beliefs and associations. Today’s Ku Klux Klan proclaims itself to be a racist organization. But in 1871 it was regarded primarily as a political one. The motives and ambitions of the Klan disturbed the Republicans in the 42d Congress because they feared that its activities would defeat the policies of Reconstruction and deprive the newly emancipated blacks of rights secured to them under the recent amendments to the Constitution. Senator John Sherman of Ohio voiced this concern after he read aloud from a copy of the Klan’s secret oath, showing that here is a political organization, with political ends, political aims; it shows that the object and intent of that political organization is to prevent large masses of the people of the southern States from enjoying a right which has been guaranteed to them by the Constitution of our country. Cong. Globe, 42d Cong., 1st Sess. 153 (1971). The Klan’s political objective formed a recurrent theme in the Senate debates. The apprehension of Republican senators over the Klan’s scheme of terrorizing citizens for their political views and of preventing voters from exercising their franchise also echoed throughout the debates conducted in the House. Representative Ellis Roberts of New York expressed this concern in the following terms: But one rule never fails: the victims whose property is destroyed, whose persons are mutilated, whose lives are sacrificed, are always Republicans. They may be black or white; they include those who wore the blue and those who wore the gray; newcomers and life-long residents, but only Republicans. Stain the door lintels with the mark of opposition to reconstruction and of hostility to the national Administration and the destroying angel passes by. Omit that sign and the torch may kindle the roof that covers women and children.... Such uniformity of result can come only from design. Republicans only are beaten and mutilated and murdered, because the blows are aimed at Republicans only. Cong. Globe, 42d Cong., 1st Sess. 412-13 (1871). Other Republican congressman expressed similar views. See generally Comment, A Construction of Section 1985(c) in Light of its Original Purpose, 46 Univ.Chi.L.Rev. 402, 407-420 (1979). Thus, whereas McLellan could locate no indication of congressional purpose to protect persons discriminated against for filing bankruptcy petitions, the legislative history reflects a pervasive concern for persons conspired against for their political associations. The congressional debates surrounding adoption of the Act therefore provide support for including within the ambit of section 1985(3) those such as the plaintiffs who are punished because of their associations. Similarly, enlarging the scope of the statute to include nonunion workers who are attacked for their choice to associate with other nonunion workers, thereby enabling an employer to offer significant work to the class, is appropriate in light of subsequently enacted federal legislation. While Congress has specifically refused to prohibit discrimination against bankrupts in legislation it has enacted on the subject, it has manifested a desire to protect laborers who opt not to affiliate themselves with a labor organization. Section 7 of the original Wagner Act provided that [ejmployees shall have the right of self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage in concerted activities, for the purpose of collective bargaining or other mutual aid or protection. Wagner Act, § 7, 49 Stat. 452 (1935). When Congress passed the original Act, it rejected the argument that parity required granting protection against coercive tactics of labor organizations as well as against those committed by employers. See S.Rep. 573, 74th Cong., 1st Sess. 16 (1935). However, significant change was not long in coming. The 1947 Taft-Hartley amendments to the National Labor Relations Act brought the addition of unfair labor practices by labor organizations. The TaftHartley Act retained the right to form, join, or assist labor organizations, but it revised section 7 of the original Act so it would contain “the right to refrain from any or all such activities.” Taft-Hartley Act, § 101, 61 Stat. 140 (1947), currently codified at 29 U.S.C. § 157. Section 8(b)(1) now declares it to be an unfair labor practice for a labor organization or its agents to restrain or coerce employees in the exercise of the rights guaranteed by section 7. 29 U.S.C. § 158(b)(1). Congress has thereby underscored the importance of the right of free association in the labor relations context and has guaranteed the right to a free and untrammeled choice to associate or not to associate with a labor organization. This manifestation of congressional concern for those in plaintiffs’ class makes their protection by section 1985(3) particularly appropriate. Finally, McLellan regarded the Supreme Court’s refusal to call the right to file a bankruptcy petition a fundamental right as relevant to its own determination that bankrupts are not protected by section 1985(3). By contrast, the Supreme Court has characterized the right of free association as “a right which, like free speech, lies at the foundation of a free society.” Shelton v. Tucker, 364 U.S. 479, 486, 81 S.Ct. 247, 251, 5 L.Ed.2d 231, 236 (1960). Our legal system honors the freedom of the individual to associate as he chooses because that freedom “tends to produce the diversity of opinion that oils the machinery of democratic government and insures peaceful, orderly change.” Gilmore v. City of Mobile, 417 U.S. 556, 577, 94 S.Ct. 2416, 2427, 41 L.Ed.2d 304, 321 (1974). The importance of the freedom of association has led the court to call it one of the “indispensable liberties,” NAACP v. Alabama ex rel. Patterson, 357 U.S. 449, 461, 78 S.Ct. 1163, 1171, 2 L.Ed.2d 1488, 1499 (1958), which ranks “among our most precious freedoms.” Williams v. Rhodes, 393 U.S. 23, 30, 89 S.Ct. 5, 10, 21 L.Ed.2d 24, 31 (1968). The right of association is fundamental in our constitutional scheme of values. Thus, the difference in importance assigned to the right to file a bankruptcy petition and the right of the individual to freely associate with others of his own choosing favors protecting these plaintiffs. Our determination that the plaintiffs constitute a protected class under section 1985(3) also comports favorably with the construction of the statute given by other courts. The lower federal courts have accorded § 1985(3) protection to two broad categories of nonracial classes. The first category consists of classes whose members are identified with one another by some inherited or immutable physical trait or by a history of past discrimination. See, e. g., Life Insurance Company of North America, 591 F.2d 499 (9th Cir. 1979) (women); Marlowe v. Fisher Body, 489 F.2d 1057 (6th Cir. 1973) (Jews); Baer v. Baer, 450 F.Supp. 481 (N.D.Cal.1978) (members of the Unification Church); Mandelkorn v. Patrick, 359 F.Supp. 692 (D.D.C.1973) (Children of God). Women, ethnic minorities, and religious sects are usually included under the statute because they are classes whose members bear no responsibility for their distinctive characteristics or because membership in the class has traditionally inflamed the irrational fears and hatreds of the majority. Thus, they may be regarded as one of the groups which “require and warrant special federal assistance in protecting their civil rights.” DeSantis v. Pacific Tel. & Tel. Co., 608 F.2d at 332-33. The plaintiffs cannot claim they are distinguished from other persons by some immutable or inherited physical trait, like race or gender, over which they have no control. However, courts have also granted protection to classes whose members are discriminated against because of their political beliefs or their associations. See, e. g., Means v. Wilson, 522 F.2d 833 (8th Cir. 1975), cert. denied, 424 U.S. 958, 96 S.Ct. 1436, 47 L.Ed.2d 364 (1976) (supporters of a particular political candidate); Glasson v. City of Louisville, 518 F.2d 899 (6th Cir.), cert. denied, 423 U.S. 930, 96 S.Ct. 280, 46 L.Ed.2d 258 (1975) (political demonstrators); Smith v. Cherry, 489 F.2d 1098 (7th Cir. 1973), cert. denied, 417 U.S. 910, 94 S.Ct. 2607, 41 L.Ed.2d 214 (1974) (voters for a sham political candidate); Cameron v. Brock, 473 F.2d 608 (6th Cir. 1973) (supporters of incumbent sheriff); Action v. Gannon, 450 F.2d 1227 (8th Cir. 1971) (worshipers at a predominantly white Catholic church disrupted by black civil rights protesters). It is within this second category of classes that plaintiffs fall. Plaintiffs were denied the equal protection of law because they did not belong to a labor organization or worked for an employer which did not have a collective bargaining agreement and which hired workers without regard to their union membership. One of the unidentified co-conspirators made it clear to the plaintiffs before the destruction began that Port Arthur was a “union town.” The plaintiffs were attacked and beaten and property was destroyed because they chose to exercise their right not to join a labor organization and to work with others of the same mind. In view of the foregoing considerations, we hold that the plaintiffs belong to a class protected by section 1985(3). Our decision does not imply that every union-nonunion controversy can create a section 1985(3) cause of action. Neither does it imply that every instance of violence arising in the context of a labor dispute will necessarily do so. Powerful limitations exist to restrict an overly broad application of the statute. See generally McLellan, 545 F.2d at 940-41 (Godbold, J., dissenting). Section 1985(3) cannot be invoked to disrupt the operation of a carefully integrated statutory scheme. See Great American Federal Savings & Loan Ass’n v. Novotny, 442 U.S. 366, 99 S.Ct. 2345, 60 L.Ed.2d 957 (1979) (holding that deprivation of a right created by Title VII cannot form the basis for § 1985(3) cause of action). Neither can a § 1985(3) cause of action be predicated upon a simple unfair labor practice. Cf. United States v. DeLaurentis, 491 F.2d 208 (2d Cir. 1974) (holding an unfair labor practice not cognizable under 18 U.S.C. § 241, the criminal analogue to section 1985(3)). Unionism or nonunionism in and of itself does not create a covered class. But where, as here, there is no campaign to organize employees and force or violence is used to deprive nonunion workers and their employer of the right to freely associate with one another, a section 1985(3) action will lie. IV. THE CONSTITUTIONAL QUESTION: THE SOURCE OF CONGRESSIONAL POWER Having determined that section 1985(3) was intended to provide a civil remedy for the kind of conspiracy involved here, we must respond to defendants’ argument that Congress lacks the constitutional power to enact legislation of this breadth. The plaintiffs maintain that section 5 of the Fourteenth Amendment authorizes Congress to provide a civil remedy for this private conspiracy. On the particular facts before us, we hold that the Commerce Clause empowers Congress to reach defendants’ conduct and do not reach the Fourteenth Amendment issue. Griffin emphasized that it was unnecessary to test the constitutionality of section 1985(3) in all conceivable applications in order to sustain its facial constitutionality and its application to the facts of any particular case. 403 U.S. at 105, 91 S.Ct. at 1799, 29 L.Ed.2d at 350. Griffin also makes clear that section 1985(3) is not unconstitutional merely because it reaches wholly private conspiracies. By the same token, it indicates that a source of congressional power must be identified to warrant application of the statute in each case. The Griffin court concluded that the Thirteenth Amendment and the constitutional right to interstate travel authorized Congress to reach the private conspiracy alleged there. But the court concluded its opinion, stating In identifying these two constitutional sources of congressional power, we do not imply the absence of any other. More specifically, the allegations of the complaint in this case have not required consideration of the scope of the power of Congress under § 5 of the Fourteenth Amendment. Id. at 107, 91 S.Ct. at 1801, 29 L.Ed.2d at 351. The plaintiffs’ § 1985(3) action cannot be sustained under the Thirteenth Amendment, for they are neither a racially oppressed group nor suffering in the bonds of involuntary servitude. See, e. g., Jones v. Mayer, 392 U.S. 409, 88 S.Ct. 2186, 20 L.Ed.2d 1189 (1968); Clyatt v. United States, 197 U.S. 207, 25 S.Ct. 429, 49 L.Ed. 726 (1905). Neither can it be supported by the right to travel on the present record. Although the plaintiffs alleged that the object of the defendants’ conspiracy was to deprive them of the right to interstate travel, they have introduced no evidence to show that either the purpose or the result of the conspirators’ acts was to infringe upon their right to such travel. However, the alternative path suggested by Griffin is itself fraught with uncertainty. A major controversy still exists over the extent to which section 5 of the Fourteenth Amendment grants Congress the power to reach wholly private conduct. Particularly, whether section 1985(3) can be constitutionally applied to private, nonracially motivated conspiracies is a question which has divided the circuits. Compare Action v. Gannon, 450 F.2d 1227 (8th Cir. 1971) and Richardson v. Milier, 446 F.2d 1247 (3d Cir. 1971) (holding that the Fourteenth Amendment authorizes Congress to reach purely private conduct) with Murphy v. Mount Carmel High School, 543 F.2d 1189 (7th Cir. 1976) (finding that it does not). Furthermore, no single interpretation of the expanse of Congress’s power under section 5 has consistently commanded the adherence of a majority of the Supreme Court. Compare United States v. Guest, 383 U.S. 745, 762, 86 S.Ct. 1170, 1180, 16 L.Ed.2d 239, 251 (1966) (Clark, J., concurring, joined by Black and Fortas, JJ.) and id. at 782, 86 S.Ct. at 1190, 16 L.Ed.2d at 263 (Brennan, J., concurring and dissenting, joined by Warren, C.J. and Douglas, J.) (suggesting that § 5 empowers Congress to punish purely private conspiracies to deprive Fourteenth Amendment rights), with, id. at 753-60, 86 S.Ct. at 1175-80, 16 L.Ed.2d at 246-250 (opinion of the Court by Stewart, J., relying on right to interstate travel) and id. at 762, 86 S.Ct. at 1180, 16 L.Ed.2d at 251, (Harlan, J., concurring and dissenting). See Oregon v. Mitchell, 400 U.S. 112, 91 S.Ct. 260, 27 L.Ed.2d 272 (1970); Katzenbach v. Morgan, 384 U.S. 641, 86 S.Ct. 1717, 16 L.Ed.2d 828 (1966). We need not depend on this uncertain precedent for congressional power. Griffin clearly contemplated that other sources of congressional power might be available to justify other applications of section 1985(3). Indeed, the original proponents of the Ku Klux Klan Act did not base their assertion of congressional power exclusively on the Fourteenth Amendment. See, e. g., Cong. Globe, 42d Cong., 1st Sess. 81 (1871) (remarks of Rep. Bingham) (“It was always competent for the Congress of the United States by law to enforce every affirmative grant of power.... ”); id. at 477-78 remarks of Rep. Shellabarger (referring to the amendment to § 2 “so far as it is not confined to infractions of rights which are clearly independent of the Fourteenth Amendment, referable to and sustained by the old provisions of the Constitution”). On the facts presented in this case, Congress has the authority to reach a wholly private conspiracy under the commerce power conferred by article I, section 8 of the Constitution. A.A. Cross Construction Company is a general contractor in the building and construction industry. The record indicates that during the year preceding the violent episode of January 17, 1975, Cross had performed work outside of Texas valued in excess of $300,000. During that same period, Cross purchased goods and materials^ which originated outside of Texas, were used in its operations within Texas, and were valued at more than $50,000. In addition, at the time of the attack on the Alligator Bayou construction site, Cross was performing its obligations under a contract with the United States Army Corps of Engineers. Article I, section 8, clause 3 of the Constitution confers upon Congress the power “[t]o regulate Commerce . . . among the several states” and clause 18 of - the same article grants it the power “[t]o make all laws which shall be necessary and proper for carrying into execution the foregoing powers. .. . ” As the Supreme Court has pointed out, this grant of power “extends to those activities intrastate which so affect interstate commerce, or the exertion of the power over it, as to make regulation of them appropriate means to the attainment of a legitimate end, the effective execution of the granted power to regulate interstate commerce.” United States v. Wrightwood Dairy Co., 315 U.S. 110, 119, 62 S.Ct. 523, 526, 86 L.Ed. 726, 732 (1942). “If it is interstate commerce that feels the pinch, it does not matter how local the operation which applies the squeeze.” United States v. Women’s Sportswear Mfg. Ass’n, 336 U.S. 460, 464, 69 S.Ct. 714, 716, 93 L.Ed. 805, 811 (1949). See United States v. Darby, 312 U.S. 100, 118, 61 S.Ct. 451, 459, 85 L.Ed. 609, 619 (1941); NLRB v. Jones & Laughlin Steel Corp., 301 U.S. 1, 37, 57 S.Ct. 615, 624, 81 L.Ed. 893, 911 (1937). Moreover, that the volume of goods and supplies purchased by Cross or that the volume of business done outside of Texas is comparatively small in terms of the total amount of goods moved or work performed in interstate commerce is not significant. Katzenbach v. McClung, 379 U.S. 294, 300-01, 85 S.Ct. 377, 382, 13 L.Ed.2d 290, 291 (1964); Wickard v. Filburn, 317 U.S. 111, 127-28, 63 S.Ct. 82, 90, 87 L.Ed. 122, 136 (1942). Judicial inquiry is limited to asking whether Congress had “a rational basis for finding a chosen regulatory scheme necessary to the protection of commerce....” Katzenbach v. McClung, 379 U.S. at 304, 85 S.Ct. at 377, 13 L.Ed.2d at 298. And it is not constitutionally relevant that Congress was actually “legislating against moral wrongs” when it enacted the provisions in question. Heart of Atlanta Motel, Inc. v. United States, 379 U.S. 241, 257, 85 S.Ct. 348, 357, 13 L.Ed.2d 258, 268 (1964). Chief Justice Marshall’s classic formulation of the extent of congressional power is still viable. Let the end be legitimate, let it be within the scope of the constitution, and all means which are appropriate which are plainly adapted to that end, which are not prohibited, but consist with the letter and spirit of the constitution, are constitutional. McCulloch v. Maryland, 4 Wheat. 316, 421, 4 L.Ed. 579, 605 (1819). By these standards, Congress acted within its constitutional power when it enacted section 1985(3) to reach the private conspiracy involved here. It cannot be denied that the aim of protecting interstate commerce from undue burdens is a legitimate end. Congress could reasonably have determined that violent attacks and vandalism perpetrated on the workers of a construction firm engaged in interstate commerce would have a disruptive effect on the flow of products and services among the states. It is also beyond dispute that the aim of protecting interstate workers in the exercise of their First Amendment associational freedoms is a legitimate end. The means adopted for the accomplishment of these ends, a private civil remedy for damages, is plainly reasonable and appropriate. Section 1985(3) as applied to the facts before us is not prohibited by the Constitution and is compatible with both its letter and its spirit. Whether section 1985(3) can constitutionally be applied to other kinds of wholly private conspiracies to deprive persons of their civil rights is a question for another day. V. THE EVIDENTIARY QUESTION: STANDARD OF PROOF AND SUFFICIENCY OF EVIDENCE A. The Standard of Proof The unions contend that they cannot be held liable for unlawful acts committed at the Cross construction site by some individual members of their organizations without “clear proof” that they actually participated in the unlawful conduct, gave prior authorization of it, or ratified the acts after actual knowledge of their commission. This more rigorous standard of proof derives from section 6 of the Norris-LaGuardia Act which provides: No officer or member of any association or organization, and no association or organization participating or interested in a labor dispute, shall be held responsible or liable in any court of the United States for the unlawful acts of individual officers, members, or agents, except upon clear proof of actual participation in, or actual authorization of, such acts, or of ratification of such acts after actual knowledge thereof. 29 U.S.C. § 106. This statutory standard of proof thus lies somewhere between the traditional burdens of reasonable doubt and preponderance of the evidence. With it, Congress intended to require “clear, unequivocal, and convincing proof” of union involvement in unlawful conduct to impose liability for it. United Mine Workers v. Gibbs, 383 U.S. 715, 737, 86 S.Ct. 1130, 1145, 16 L.Ed.2d 218, 234 (1966). Yet, while section 106 requires clear and convincing evidence as to union authorization, participation in, or ratification of the acts allegedly performed by its members, it does not prescribe a different standard of proof for other issues in actions against a union or its officers or members involved in a labor dispute. Ramsey v. United Mine Workers, 401 U.S. 302, 91 S.Ct. 658, 28 L.Ed.2d 64 (1971). The unions also recognize that section 106 is by its own terms limited to cases in which the union is participating or interested in a labor dispute. The Norris-LaGuardia Act defines a “labor dispute” to encompass any controversy concerning terms and conditions of employment, or concerning the association or representation of persons in negotiating, fixing, maintaining, charging, or seeking to arrange terms or conditions of employment, regardless of whether or not the disputants stand in the proximate relation of employer and employee. 29 U.S.C. § 113(c). The unions insist that the literal language of section 113(c) squarely covers the conduct at issue here. The persons who planned and executed the attack on the Alligator Bayou construction site were motivated by their resentment of Cross’s employment practices and hostility toward its nonunion workers. Because the conspiracy that generated the case was formed around this nonunion animus, the defendants maintain that the controversy out of which this case arose cannot be anything other than a labor dispute. This approach has a certain superficial appeal. Doubtless the attack on the Cross construction site was conceived in reprisal for the refusal of Cross and his workers to accede to demands that the Alligator Pumping Station project be conducted as a union job. Neverthe