Full opinion text
REINHARDT, Circuit Judge. This appeal presents a challenge to the constitutionality of the Partial-Birth Abortion Ban Act of 2003, Pub.L. No. 108-105, 117 Stat. 1201 (codified at 18 U.S.C. § 1531). We, like every other federal court that has considered the question, conclude that both the Constitution and the law as established by the Supreme Court require us to hold the Act unconstitutional. Unlike the other courts, however, we do so after fully considering the Supreme Court’s recent decision in Ayotte v. Planned Parenthood of N. New England, — U.S. -, 126 S.Ct. 961, — L.Ed.2d - (2006). In light of Ayotte, we conclude that the only appropriate remedy is to enjoin enforcement of the Act and we now affirm the district court’s grant of a permanent injunction. I. Background A. Postr-First Trimester Abortion Methods The vast majority of abortions in the United States are performed during the first trimester. Approximately ten percent of abortions are performed during the second trimester. Only about one percent are performed after the twentieth week from the woman’s last menstrual period (“Imp”) and only a small portion of those after the twenty-fourth week, the earliest time at which viability begins. In short, only a tiny percentage of abortions are performed after viability may have commenced. Women seek abortions after the first trimester for various reasons, including newly discovered fetal anomalies and maternal health problems that are created or exacerbated by the pregnancy. This is primarily because ultrasound and amniocentesis — procedures that often detect these medical conditions — generally are not available until the second trimester. Because abortions are rarely performed after the twenty-fourth week Imp and even more rarely after the second trimester (in both cases almost always for medical reasons), the Act essentially regulates previa-bility second trimester abortions. Nearly all post-first trimester abortions are performed using one of two methods: dilation and evacuation (“D & E”) or induction. D & E accounts for 85 to 95 percent of such abortions. Unlike induction, which is a form of “medical” abortion, D & E is a surgical procedure involving two steps: dilation of the cervix and surgical removal (evacuation) of the fetus. There are two forms of D & E, intact and non-intact. The first step of the procedure, cervical dilation, is the same for both forms of D & E. It is achieved primarily through the use of osmotic dilators, which are sponge-like devices that expand the cervix, typically over a period of twenty-four to forty-eight hours. Some doctors also use medications known as prostaglandins in conjunction with the osmotic dilators, though these drugs sometimes induce labor spontaneously, which results in partial or complete expulsion. The dilation process is necessary so that the doctor may insert an instrument, generally a type of forceps, through the cervix and into the uterus in order to remove the fetus. The second step of the procedure, the evacuation phase, is when the two forms of D & E become different. When performing a non-intact D & E, the doctor, under ultrasound guidance, grasps a fetal extremity with forceps and attempts to bring the fetus through the cervix. At this point, the fetus will ordinarily disarticu-late, or break apart, because of traction from the cervix, and the doctor must return the instrument to make multiple passes into the uterus to remove the remaining parts of the fetus, causing further disarticulation. To complete the removal process, the doctor evacuates the placenta and any remaining material using a suction tube, or cannula, and a spoon-like instrument called a curette. In an intact D & E, the doctor, rather than using multiple passes of the forceps to disarticulate and remove the fetus, removes the fetus in one pass, without any disarticulation occurring (i.e., the fetus is “intact”). An intact D & E proceeds in one of two ways, depending on the position of the fetus in the uterus. If the fetus presents head first (a vertex presentation), the doctor first collapses the head, either by compressing the skull with forceps or by inserting surgical scissors into the base of the skull and draining its contents. The doctor then uses forceps to grasp the fetus and extracts it through the cervix. If the fetus presents feet first (a breech presentation), the doctor begins by grasping a lower extremity and pulling it through the cervix, at which point the head typically becomes lodged in the cervix. When that occurs, the doctor can either collapse the head and then remove the fetus or continue pulling to disarticulate at the neck. (If the doctor uses the latter option, he will have to use at least one more pass of the forceps to remove the part of the fetus that remains, and the procedure is not considered an intact D & E.) As the district court found, some doctors prefer to use the intact form of D & E, whenever possible, because they believe it offers numerous safety advantages over non-intaet D & E. As the district court also found, intact D & E may be significantly safer than other D & E procedures because it involves fewer instrument passes, a shorter operating time and consequently less bleeding and discomfort for the patient, less likelihood of retained fetal or placental parts that can cause infection or hemorrhage, and little or no risk of laceration from bony fetal parts. Finally, as the district court found, intact D & E is in fact the safest medical option for some women in some circumstances. For example, women with specific health conditions and women who are carrying fetuses with certain abnormalities benefit particularly from the availability of the intact D & E procedure. According to the American College of Obstetricians and Gynecologists (“ACOG”), the safety advantages offered by intact D & E mean that in certain circumstances it “may be the best or most appropriate procedure ... to save the life or preserve the health of a woman.” Doctors typically decide whether to attempt an intact D & E based primarily on the amount of cervical dilation, but they can never predict beforehand whether they will be able ultimately to remove the fetus intact. In most cases, intact D & E is not an option from the outset; in others, although the procedure may start out as an intact removal, during the course of the procedure it turns into a non-intact D & E. As explained further below, the government construes the Act as prohibiting intact D & Es but permitting non-intact D & Es, whereas the plaintiffs assert that it covers both forms of the procedure, as well as induction. The plaintiffs also contend that even if the Act banned only intact D & Es, it would still be unconstitutional. B. The Statute Enacted in response to the Supreme Court’s decision in Stenberg v. Carhart, 530 U.S. 914, 120 S.Ct. 2597, 147 L.Ed.2d 743 (2000), which declared a Nebraska statute regulating “partial-birth abortions” unconstitutional, the Act subjects any physician who “knowingly performs a partial-birth abortion” to civil and criminal penalties, including up to two years of incarceration. 18 U.S.C. § 1531(a) (2005). The Act’s definition of “partial-birth abortion” covers an abortion performed by any doctor who: (A) deliberately and intentionally vaginally delivers a living fetus until, in the case of a head-first presentation, the entire fetal head is outside the body of the mother, or, in the case of breech presentation, any part of the fetal trunk past the navel is outside the body of the mother, for the purpose of performing an overt act that the person knows will kill the partially delivered living fetus; and (B) performs the overt act, other than completion of delivery, that kills the partially delivered living fetus. 18 U.S.C. § 1531(b)(1). Doctors who perform a “partial-birth abortion” are exempt from criminal liability only when the procedure is “necessary to save the life of a mother whose life is endangered by a physical disorder, physical illness, or physical injury, including a life-endangering physical condition caused by or arising from the pregnancy itself.” 18 U.S.C. § 1531(a). The Act does not contain an exception for abortions that are necessary to preserve the health of the woman. Congress made several findings of fact in support of its determination that the Act’s prohibition did not require a health exception. Partial-Birth Abortion Ban Act § 2(8)-(13). Most significant, Congress found that: There exists substantial record evidence upon which Congress has reached its conclusion that a ban on partial-birth abortion is not required to contain a ‘health’ exception, because the facts indicate that a partial-birth abortion is never necessary to preserve the health of a woman, poses serious risks to a woman’s health, and lies outside the standard of medical care. Id. at § 2(13) (emphasis added). Another of Congress’s central findings was that a “moral, medical and ethical consensus” exists that intact D & E is “never medically necessary and should be prohibited.” Id. at § 2(1). C. The Litigation Directly after President George W. Bush signed the Act into law on November 5, 2003, the plaintiffs filed this lawsuit claiming that the Act violates rights guaranteed by the U.S. Constitution. The City and County of San Francisco intervened as a plaintiff. On November 6, 2003, the district court issued a temporary injunction against enforcement of the Act. At the government’s request, the district court consolidated the preliminary injunction hearing and the trial on the merits. After an approximately three-week trial in which it heard the testimony of thirteen expert witnesses, the district court found the Act unconstitutional and entered a permanent injunction against its enforcement. Planned Parenthood Fed’n of Am. v. Ashcroft, 320 F.Supp.2d 957, 1034-35 (N.D.Cal.2004). The district court’s holding rested on its determination that the Act violated the Constitution in three respects. First, the district court found the Act unconstitutional because it imposed an undue burden on a woman’s right to choose to terminate her pregnancy before viability. The court concluded that the Act’s definition of “partial-birth abortion” reached all D & E procedures as well as certain induction ■ abortions. Because D & E and induction procedures comprise nearly all post-first trimester abortions, the district court concluded that the Act created a risk of criminal liability for virtually all abortions performed after the first trimester, which, the district court found, placed a substantial obstacle in the path of abortion-seekers. In the alternative, the court found that the Act created an undue burden even if construed to apply only to intact D & Es. It found that the failure to distinguish between previability and post-viability abortions placed a substantial obstacle in the path of women who seek or require an intact D & E prior to viability, even under the unconvincing alternate construction of the statute. Second, the district court found the Act unconstitutionally vague. The court reasoned that the term “partial-birth abortion” was not recognized in the medical community, and the phrases “living fetus,” “deliberately and intentionally,” and “overt act” failed to put physicians on notice as to what procedures would violate the statute. As a result, the district court found that the Act deprived physicians of fair notice and encouraged arbitrary enforcement. The district court held that the inclusion of scienter requirements did not remedy the vagueness. Third, the district court found the Act unconstitutional because it failed to include a health exception. The court held that as a preliminary matter, it need not decide the highly disputed issue of the proper standard of deference applicable to Congress’s findings because, even under the most deferential standard of review, Congress’s finding that the prohibited procedures were never medically necessary to preserve women’s health was not entitled to controlling deference. Instead, the court, on the basis of the record before Congress at the time it passed the Act, the record before the district court and Supreme Court in Stenberg, and the record adduced by the parties in the present case, concluded that the Act’s failure to include a health exception rendered it unconstitutional. D. Other Federal Courts’ Treatment of the Act In addition to the district court, three other federal courts have reviewed the Act and each has held it unconstitutional. The Eighth Circuit declared the Act unconstitutional because it failed to contain an exception for women’s health as required under Stenberg. Carhart v. Gonzales, 413 F.3d 791, 803-04 (8th Cir.2005). The district court in that case also found the Act unconstitutional because of the lack of a health exception, as well as because it imposed an undue burden on a woman’s ability to choose a previability, post-first trimester abortion. Carhart v. Ashcroft, 331 F.Supp.2d 805, 809 (D.Neb.2004). Finally, the District Court for the Southern District of New York found the Act unconstitutional because it did not contain a health exception. Nat’l Abortion Fed’n. (“NAF”) v. Ashcroft, 330 F.Supp.2d 436, 492-493 (S.D.N.Y.2004). None of these courts considered separately the question of remedy because under Stenberg, 530 U.S. at 946, 120 S.Ct. 2597, enjoining enforcement of the Act appeared to be mandatory at the time the decisions were issued. Ayotte, 126 S.Ct. at 969. II. Standard of Review We review an order granting a permanent injunction for abuse of discretion or application of erroneous legal principles, Forbyune v. Am. Multi-Cinema, Inc., 364 F.3d 1075, 1079 (9th Cir.2004), but review determinations underlying such a grant by the standard that applies to such determinations. Ting v. AT & T, 319 F.3d 1126, 1134-35 (9th Cir.2003). As a result, underlying legal rulings are reviewed de novo and underlying factual findings are reviewed under the clearly erroneous standard. Id. The question whether the Act imposes an undue burden or is unconstitutionally vague is a legal issue subject to de novo review. Planned Parenthood of S. Ariz. v. Lawall (“Lawall II”), 307 F.3d 783, 786 (9th Cir.2002). In analyzing a facial challenge to an abortion statute, we apply the undue burden standard established in Planned Parenthood of Southeastern Pa. v. Casey, 505 U.S. 833, 895, 112 S.Ct. 2791, 120 L.Ed.2d 674 (1992). Lawall II, 307 F.3d at 786. “[T]he fact that the statute is susceptible to some constitutional application will not save it from facial attack. Rather, we must be satisfied that it will pose an undue burden in only a small fraction of relevant cases.” Planned Parenthood of Idaho Inc. v. Wasden, 376 F.3d 908, 921 (9th Cir.2004); see also Richmond Med. Ctr. for Women v. Hicks, 409 F.3d 619, 627-28 (4th Cir.2005) (noting the recent Supreme Court case Sabri v. United States, 541 U.S. 600, 124 S.Ct. 1941, 158 L.Ed.2d 891 (2004), makes clear that the “no set of circumstances” test for facial challenges from United States v. Salerno, 481 U.S. 739, 107 S.Ct. 2095, 95 L.Ed.2d 697 (1987), “does not apply in the context of a facial challenge, like the one here, to a statute regulating a woman’s access to abortion”). When the question concerns the existence of an adequate health exception, “facial challenges may prevail in an even broader group of cases: those where a law could preclude an abortion where it is necessary, in appropriate medical judgment, for the preservation of the life or health of the mother.” Wasden, 376 F.3d at 921 n. 10 (citing Stenberg, 530 U.S. at 930, 120 S.Ct. 2597) (internal quotation marks omitted); see also Carhart, 413 F.3d at 795 (“[I]f the Act fails the Stenberg test, it must be held facially unconstitutional.”); Women’s Med. Prof'l Corp. v. Voinovich, 130 F.3d 187, 196 (6th Cir.1997) (“[A] post-viability abortion regulation which threatens the life or health of even a few pregnant women should be deemed unconstitutional.”), quoted in Planned Parenthood of Rocky Mountains Serv. v. Owens, 287 F.3d 910, 919 (10th Cir.2002). When determining the remedy for a statute found to be unconstitutional, we are guided by “three interrelated principles”: one, we try to invalidate no more of a statute than is necessary to remedy the constitutional violation; two, we are mindful that the limited judicial role and our institutional competence prevent us from rewriting a statute in order to make it constitutional; and three, any remedy we devise must be faithful to the legislative intent in enacting the statute. Ayotte, at 967-969. III. Analysis We hold that the Act is unconstitutional for three distinct reasons, each of which is sufficient to justify the district court’s holding. First, the Act lacks the constitutionally required health exception. Second, it imposes an undue burden on women’s ability to obtain previability abortions. Third, it is unconstitutionally vague, depriving physicians of fair notice of what it prohibits and encouraging arbitrary enforcement. For reasons explained in Section IV infra, we conclude that the appropriate remedy is to enjoin the enforcement of the Act. We therefore affirm the district court’s issuance of the permanent injunction. A. The Act Is Unconstitutional Because It Lacks Any Exception to Preserve the Health of the Mother We hold that the omission of a health exception from the Act renders it unconstitutional. In reaching that conclusion, we first determine whether and in what circumstances a statute that regulates abortion but lacks a health exception is constitutional under Stenberg. Next, we consider the proper standard of review for the findings Congress made in support of its omission of a health exception from the Act. Finally, in light of this analysis, we assess the Act and the congressional findings that bear on its constitutionality. i. The Standard for Evaluating Abortion Restrictions that Lack a Health Exception Our analysis of whether the Act’s lack of a health exception renders it unconstitutional is controlled by Stenberg and Casey. Stenberg reaffirms Casey’s holding that the Constitution requires that any abortion regulation must contain such an exception if the use of the otherwise regulated procedure may in some instances be necessary to preserve a woman’s life or health. Wasden, 376 F.3d at 922; see also Hicks, 409 F.3d at 625. Stenberg holds that an abortion regulation that fails to contain a health exception is unconstitutional except when there is a medical consensus that no circumstance exists in which the procedure would be necessary to preserve a woman’s health. 530 U.S. at 937, 120 S.Ct. 2597. By medical consensus, we do not mean unanimity or that no single doctor disagrees, but rather that there is no significant disagreement within the medical community. The Stenberg holding implements the health exception requirement announced in Casey. Casey held that even when the state’s interest in regulating abortion is at its height (i.e., postviability), any restriction of an abortion method must include an exception when that method “ ‘is necessary, in appropriate medical judgment, for the preservation of the life or health of the mother’ ” in some circumstances. Stenberg, 530 U.S. at 921, 120 S.Ct. 2597 (quoting Casey, 505 U.S. at 879, 112 S.Ct. 2791 (quoting Roe v. Wade, 410 U.S. 113, 164-65, 93 S.Ct. 705, 35 L.Ed.2d 147 (1973))). The Supreme Court noted that the phrase “necessary, in appropriate medical judgment” does not require “absolute necessity,” “absolute proof,” or “unanimity of medical opinion” regarding the need for the use of the regulated procedure to preserve women’s health in some instances. Stenberg, 530 U.S. at 937, 120 S.Ct. 2597. In fact, the Court emphasized that, for purposes of Casey’s requirement that an abortion ban have a health exception, “division of medical opinion ... signals the presence of risk, not its absence,” and thus compels the inclusion of the exception in the statute. Id. Because “uncertainty” or division in the medical community regarding the need for a health exception “means a significant likelihood that those who believe that [a particular type of abortion procedure] is a safer abortion method in certain circumstances [than the alternatives] may turn out to be right,” the Court held that as long as there is a lack of consensus in that community, any regulation of an abortion method must contain a health exception. Id. at 937-38, 120 S.Ct. 2597. Without a medical consensus, the Court stated, it is impossible for a legislative body to determine that “a health exception is never necessary to preserve the health of women” and, in such circumstance, any abortion regulation the legislature enacts without a health exception is unconstitutional. Id. (internal quotation marks omitted); see also Carhart, 413 F.3d at 796 (“[W]e believe when a lack of consensus exists in the medical community, the Constitution requires legislatures to err on the side of protecting women’s health by including a health exception.”). Under the constitutional rule established in Stenberg, therefore, we must inquire whether — applying the appropriate degree of deference to the legislative body’s findings — the legislature properly concluded that there is consensus in the medical community that the banned procedure is never medically necessary to preserve the health of women. See NAF, 330 F.Supp.2d at 488. ii. Identifying and Applying the Appropriate Level of Deference to Congress’s Factual Findings in the Act Having identified the inquiry we must undertake in order to assess the constitutionality of the Act’s lack of a health exception, we now turn to the level of deference we must apply to the relevant congressional findings. Here, Congress omitted a health exception because it found that “the facts indicate that a partial-birth abortion is never necessary to preserve the health of a woman,” Partial-Birth Abortion Ban Act § 2(13), and that a “moral, medical and ethical consensus” exists that “partial-birth abortion” is “never medically necessary and should be prohibited.” Id. at § 2(1). Under Stenberg, the former finding is dependent on the validity of the latter. The government and many of the amici argue that Congress’s findings of fact in this case should be evaluated under the standard articulated by the Court in Turner Broadcasting System v. FCC (“Turner II”), 520 U.S. 180, 117 S.Ct. 1174, 137 L.Ed.2d 369 (1997), and related cases. Under this standard, when reviewing findings of fact that bear on the constitutionality of a statute, a reviewing court need only “ ‘assure that, in formulating its judgments, Congress has drawn reasonable inferences based on substantial evidence.’ ” Id. at 195, 117 S.Ct. 1174 (quoting Turner Broad. Sys. v. FCC (“Turner I”), 512 U.S. 622, 666, 114 S.Ct. 2445, 129 L.Ed.2d 497 (1994)). The Court has explained that when applying the substantial evidence standard, “the possibility of drawing two inconsistent conclusions from the evidence does not prevent ... [a] finding from being supported by substantial evidence.” Turner II, 520 U.S. at 211, 117 S.Ct. 1174 (internal quotation marks and citations omitted). The appellants and other amici, however, strongly argue that Turner does not apply to evaluations of the Act’s constitutionality. As an initial matter, we note that the Court’s treatment of the level of deference to be applied to congressional findings that bear on the constitutionality of statutes has been less than clear. In some cases, the Court has expressly applied the substantial evidence standard described in Turner and related decisions. See, e.g., McConnell v. FEC, 540 U.S. 93, 165, 124 S.Ct. 619, 157 L.Ed.2d 491 (2003). In others, the Court, without mentioning Turner or substantial evidence, and without identifying the standard of review it is applying, has reviewed congressional findings of fact with considerably less deference. See, e.g., Bd. of Trustees of Univ. of Ala. v. Garrett, 531 U.S. 356, 368-72, 121 S.Ct. 955, 148 L.Ed.2d 866 (2001); United States v. Morrison, 529 U.S. 598, 609-13, 120 S.Ct. 1740, 146 L.Ed.2d 658 (2000). Considered together, these cases make it difficult to identify the proper standard to be applied to congressional findings that bear on the constitutionality of certain statutes; in fact, they suggest that no single standard exists. Fortunately, we need not resolve the question of the proper standard of review for findings made pursuant to the Act. Under even the most deferential level of review, the one identified as applicable in Congress’s findings and by the government in its arguments to this court, we cannot defer to the critical congressional finding in this case: that there is a consensus in the medical community that the prohibited procedures are never necessary to preserve the health of women choosing to terminate their pregnancies. The record before Congress clearly demonstrates that no such consensus exists, as do the congressional findings themselves. As a result, we cannot uphold the finding to the contrary, even if we apply substantial evidence review. Although Congress found that “[a] moral, medical, and ethical consensus exists that the practice of performing a partial-birth abortion ... is never medically necessary,” Partial-Birth Abortion Ban Act § 2(1), that finding is directly belied by another of Congress’s findings and by the record that Congress developed in support of the legislation. The evidence of the lack of medical consensus is replete throughout that record and is confirmed in a significant statutory finding. As the district court pointed out, “Congresses] very findings contradict its assertion that there is a consensus. Congress subsequently noted in its findings that ‘a prominent medical association,’ the AMA, concluded that ‘there is no consensus among obstetricians about’ the use of intact D & E.” Planned Parenthood, 320 F.Supp.2d at 1025 (citing Partial-Birth Abortion Ban Act § 2(14)(C)) (emphasis added). The district court also noted that “Congress ... had before it a joint statement from the AMA and ACOG, the two largest medical organizations taking positions on the issue, which recognized the disagreement among and within the two organizations.” Id. at 1025. Furthermore, “nearly half (22 out of 46) of all individual physicians who expressed non-conclusory opinions to Congress” stated that the banned procedures were necessary in at least some circumstances, as did professors of obstetrics and gynecology from many of the nation’s leading medical schools. Carhart, 331 F.Supp.2d at 1009; see also Planned Parenthood, 320 F.Supp.2d at 1025-26 (describing other evidence before Congress demonstrating a lack of medical consensus). The evidence before Congress at the time it passed the Act, as well as other evidence presented during litigation, has led every court that has considered the statute’s constitutionality to conclude that no medical consensus exists that the abortion procedures outlawed by the Act are never necessary to preserve the health of a woman — and we agree. See Carhart, 413 F.3d at 802 (“If one thing is clear from the record in this case, it is that no consensus exists in the medical community. The record is rife with disagreement on this point, just as in Stenberg.”); Carhart, 331 F.Supp.2d at 1008 (“In fact, there was no evident consensus in the record that Congress compiled. There was, however, a substantial body of medical opinion presented to Congress in opposition.”); id. at 1009 (“Based upon its own record, it was unreasonable to find, as Congress did, that there was ‘consensus’ of medical opinion supporting the ban. Indeed, a properly respectful review of that record shows that a substantial body of contrary, responsible medical opinion was presented to Congress. A reasonable person could not conclude otherwise.”); NAF, 330 F.Supp.2d at 482 (“There is no consensus that [intact D & E] is never medically necessary, but there is a significant body of medical opinion that holds the contrary.”); Planned Parenthood, 320 F.Supp.2d at 1025 (“[T]he evidence available to Congress in passing the Act in 2003, and currently before this court, very clearly demonstrates ... that there is no medical or ethical consensus regarding either the humanity, necessity, or safety of the procedure.”). The government all but admits in its reply brief that no medical consensus ex7 ists regarding the need for the prohibited procedures to preserve the health of women in certain circumstances. See Appellant’s Reply Brief at 25 (admitting that “both sides now concede the existence of ‘contradictory evidence’ in the congressional and trial records”). Nonetheless, it argues that the lack of consensus regarding whether the procedures prohibited by the Act are ever necessary to preserve the health of women is irrelevant because under Turner courts must resolve reasonable factual disagreements in favor of congressional findings. The flaw in the government’s argument is not the standard of review it invokes, which may or may not be correct, but the factual dispute it identifies as relevant. In reviewing the Act’s lack of a health exception, the dispositive question is not, as the government asserts, whether Congress’s finding that the prohibited procedures are never necessary to preserve the health of a mother offers a reasonable (or plausible) resolution of a genuine factual dispute (which incidentally the record shows it does ■ not). Rather, under Stenberg, it is whether there is general agreement in the medical community that there are no circumstances in which the procedure would be necessary to preserve a woman’s health. Even the most cursory review of the Act and the congressional record developed in support of it reveals that no such medical consensus exists, a fact that the government essentially concedes in its brief to this court and that is fully confirmed by the evidence introduced in the district court during trial. Thus, whether we use Turner’s substantial evidence test or a more rigorous standard, under no circumstances would the record permit us to uphold a finding that meets the Stenberg requirement of the absence of a division of opinion in the medical community. We conclude that we cannot defer to Congress’s finding that the procedures banned by the Act are never required to preserve the health of women; to the contrary, we are compelled to conclude, on the basis of the record before Congress, of the congressional findings themselves, and of evidence introduced in the district court, that a substantial disagreement exists in the medical community regarding whether those procedures are necessary in certain circumstances for that purpose. In such circumstance, we are compelled to hold that a health exception is constitutionally required. We therefore affirm the district court’s holding that Congress’s failure to include a health exception in the statute renders the Act unconstitutional. B. The Act is Unconstitutional Because It Imposes an Undue Burden on Women’s Right to Choose a Previability Abortion In addition to its lack of a health exception, the Act suffers from other major deficiencies that lead us to conclude that it is unconstitutional, including the undue burden it imposes on a woman’s constitutional right to choose to have an abortion before the fetus is viable. The Constitution -guarantees a woman the right to choose to terminate a previability pregnancy. Stenberg, 530 U.S. at 921, 120 S.Ct. 2597 (quoting Casey, 505 U.S. at 870, 112 S.Ct. 2791); Tucson Woman’s Clinic v. Eden, 379 F.3d 531, 539 (9th Cir.2004) (as amended); Wasden, 376 F.3d at 921. Although the Constitution firmly guarantees women that right, the state may seek to protect its interest in fetal life by regulating the means by which abortions may be secured, provided the regulations do not impose an “undue burden” on a woman’s ability to obtain an abortion. Stenberg, 530 U.S. at 921, 120 S.Ct. 2597; Casey, 505 U.S. at 874, 112 S.Ct. 2791; see also Tucson Woman’s Clinic, 379 F.3d at 539; Wasden, 376 F.3d at 921. An “ ‘undue burden is ... shorthand for the conclusion that a state regulation has the purpose or effect of placing a substantial obstacle in the path of a woman seeking an abortion of a nonviable fetus.’ ” Stenberg, 530 U.S. at 921, 120 S.Ct. 2597 (quoting Casey, 505 U.S. at 877, 112 S.Ct. 2791). In Stenberg, the Court held that a Nebraska statute regulating so-called “partial-birth abortions” imposed an undue burden. Without deciding the issue whether a statute that outlawed only intact D & Es would be unduly burdensome, the Stenberg court held that an abortion ban that failed to differentiate in its statutory language between intact D & Es and non-intact D & Es unquestionably constituted an undue burden, for the obvious reason that it would prohibit most second trimester abortions. Stenberg, 530 U.S. at 938-46, 120 S.Ct. 2597. As part of its analysis, the Stenberg Court provided legislatures with guidance about how to draft statutes that would adequately distinguish between the two forms of D & E. The Court explained that a legislature can make clear that a statute intended to regulate only intact D & Es applies to that form of the procedure only, by using language that “track[s] the medical differences between” intact and non-intact D & Es or by providing an express exception for the performance of non-intact D & Es and other abortion procedures. Stenberg, 530 U.S. at 939, 120 S.Ct. 2597. In her concurring opinion, Justice O’Connor emphasized how by employing the latter approach, a legislature could easily make clear that a statute intended to regulate intact D & E was in fact narrowly tailored to reach only that form of the D & E procedure. Stenberg, 530 U.S. at 950, 120 S.Ct. 2597 (O’Connor, J., concurring). Citing three state statutes prohibiting intact D & Es which had “specifically excluded] from their coverage” other abortion methods, Justice O’Connor described the language each statute used, providing legislatures wishing to prohibit only intact D & Es with a clear roadmap for how to avoid the problems regarding the scope of coverage that undid the Nebraska statute. Id. When drafting the Act, however, Congress deliberately chose not to follow the Court’s guidance. See Section IV infra. The Act’s definition of the prohibited procedures does not attempt to track the medical differences between intact D & E and other forms of D & E, nor does it explicitly exclude non-intact D & Es from its reach. Instead of using either of these approaches for accomplishing the objective the government embraces in its brief— prohibiting only intact D & Es, Congress defined the prohibited procedure in a way that a number of doctors have explained includes both intact and non-intact D & Es, and that we likewise conclude bans both forms of the procedure. Because the Act, like the statute invalided in Stenberg, would allow prosecutors to pursue physicians who “use [non-intact] D & E procedures, the most commonly used method for performing previability second trimester abortions” and would cause all doctors performing those procedures to “fear prosecution, conviction, and imprisonment,” Stenberg, 530 U.S. at 945, 120 S.Ct. 2597, it too is unconstitutional. Neither the differences the government cites between the language of the Act and the Nebraska statute nor the scienter requirements contained in the Act limit its application to the intact D & E procedure and neither, therefore, serves to cure the statute’s constitutional infirmity. i The Act Encompasses Non-Intact D & E Procedures The government offers no explanation for why Congress did not adopt either of the two approaches outlined by the Court and Justice O’Connor in Stenberg for legislating a prohibition that is applicable only to the intact D & E procedure. Rather, it asserts that the federal statute differs from the Nebraska statute invalidated in Stenberg in three significant respects that collectively make it clear that the Act applies only to that form of the procedure. It argues that, as a result, the Act is constitutional although the Nebraska law was not. The differences in statutory language to which the government points fall far short, however, of adequately differentiating between the two forms of D & E, much less of achieving the degree of certainty regarding the Act’s scope that Congress could have easily accomplished had it followed Stenberg, either by tracking the medical differences between intact D & E and other forms of D & E or by specifying that the forms of D & E other than the intact version are not covered by the prohibition. The three differences between the Act and the Nebraska statute that the government relies on are as follows. First, the government notes that unlike the Nebraska statute which applied when the living fetus or a substantial portion of it was delivered “into the vagina,” Neb.Rev.Stat. § 28-326(9), the federal Act applies only when there is a vaginal delivery “outside the body of the mother,” 18 U.S.C. § 1531(b)(1)(A). The government argues that because non-intact D & E generally involves dismemberment of the fetus before it leaves the mother’s body, the specification that the Act applies only when a living fetus or a part thereof is delivered outside the mother’s body makes clear that the Act does not apply to that procedure. The government’s claim is incorrect. As the record demonstrates and the district court found, in non-intact D & Es, a doctor may extract a substantial portion of the fetus — including either a part of the fetal trunk past the navel or the entire fetal head- — to the point where it is outside the body of the mother before the fetal disarti-culation occurs. Although different from the provision in the Nebraska statute, the “outside the body of the mother” provision does not limit the Act’s reach to intact D & Es and, as a result, does not eliminate the undue burden the Act imposes. Second, the Nebraska statute applied only when “a living unborn child, or a substantial portion thereof’ is delivered for the purpose of performing a prohibited act, Neb.Rev.Stat. § 28-326(9), whereas the federal Act states its prohibition applies only when either the “entire fetal head” or “any part of the fetal trunk past the navel” of a living fetus is delivered for a similar purpose, 18 U.S.C. § 1531(b)(1)(A). The government argues that the use of a “specific anatomic landmark” addresses the concern the Supreme Court expressed with the “substantial portion” language of the Nebraska statute. As with the first difference relied upon by the government, however, the “specific anatomic landmark” language makes the Act different from the Nebraska statute but does not exclude non-intact D & Es from the Act’s coverage. As the district court found, intact D & Es are not the only form of D & E in which the “entire fetal head” or “any part of the fetal trunk past the navel” of a living fetus may be delivered prior to the performance of an act banned by the statute: the “anatomic landmark” specified in the Act may be reached by doctors performing either intact or non-intact D & Es. Accordingly, this second difference from the Nebraska statute, like the first, does not establish that the Act is applicable only to intact D & Es. Third, the Nebraska statute applied when a doctor “deliberately and intentionally deliver[s] into the vagina a living unborn child, or a substantial portion thereof, for the purpose of performing a procedure that the person performing such procedure knows will kill the unborn child and does kill the unborn child.” Neb.Rev.Stat. § 28-326(9) (emphasis added). The federal statute, however, requires that a doctor “deliberately and intentionally vaginally deliver[ ] a living fetus ... for the purpose of performing an overt act that the person knows will kill the partially delivered living fetus ” and “perform [] the overt act, other than completion of delivery, that kills the partially delivered living fetus." 18 U.S.C. § 1531(b)(1)(A), (B). The government argues that this “overt act” requirement unambiguously establishes that the Act does not apply to abortion procedures other than intact D & Es. However, this language is also not as restrictive as the government claims. In non-intact D & Es, as well as in the intact form of the procedure, if the fetus has been brought to either of the two anatomic landmarks specified in the Act, a doctor may then, in order to complete the abortion safely, need to perform an “overt act,” other than completing delivery, that the physician knows the fetus cannot survive, if it is still living, and that “kills” the fetus. The “overt act” that may be performed in a non-intact D & E includes disarticulating the fetus or compressing the abdomen or other fetal part that is obstructing the completion of the uterine evacuation. As with the other two differences in the statutory language that the government claims clearly establish that the Act applies only to intact D & E, the “overt act” language does not so restrict the Act’s applicability. Contrary to the government’s claim, properly construed the Act covers non-intact as well as intact D & Es. As a result, despite containing some provisions that are different in form from those in the Nebraska statute, the Act is sufficiently broad to cause those who perform non-intact D & E procedures to “fear prosecution, conviction, and imprisonment.” Stenberg, 530 U.S. at 945, 120 S.Ct. 2597. The resulting chilling effect on doctors’ willingness to perform previability post-first trimester abortions would impose an undue burden on the constitutional rights of women. Id. ii. The Act’s Scienter Requirements Do Not Cure the Constitutional Infirmity The government also argues that the Act’s scienter requirements preclude application of the statute to physicians who perform non-intact D & E procedures and that the federal statute should therefore survive constitutional scrutiny. Although the Act does limit its reach to those who “knowingly perform a partial-birth abortion,” 18 U.S.C. § 1531(a) (emphasis added), and “deliberately and intentionally vaginally deliver[ ] a living fetus until, in the case of a head-first presentation, the entire fetal head is outside the body of the mother, or, in the case of breech presentation, any part of the fetal trunk past the navel is outside the body of the mother,” 18 U.S.C. § 1531(b)(1)(A) (emphasis added), these scienter requirements do not permit us to interpret the Act as reaching only the intact D & E procedure. The government’s argument about the restrictive effect of the statute’s scienter requirements depends on the premise that, once the scienter requirements are applied, the Act’s description of the prohibited procedure includes only intact D & Es. However, that is simply not the case. The actions described in the statute’s definition of the prohibited procedure can be performed with the requisite intent in both the intact and the non-intact forms of the D & E procedure. For instance, the record shows that a doctor performing a non-intact D & E of a fetus in the breech position may, in order to minimize the number of disarticulated fetal parts removed from the woman’s body, “deliberately and intentionally vaginally deliver! ] a living fetus until ... the fetal trunk past the navel is outside the body of the mother” before performing the acts of disarticu-lation. Such an abortion meets all of the requirements of the procedure outlawed by the Act — the doctor knowingly, deliberately, and intentionally vaginally delivers the fetus to the specific anatomic landmark and does so for the purpose of performing an “overt act [the disarticulation] that [he] knows will kill the partially delivered living fetus” and performs that act. See, e.g., Brief of Amici Curiae the California Medical Association et al. at 22. Even with the Act’s scienter requirements, therefore, non-intact D & Es readily fall within the scope of the statute’s description of the banned procedure. As a result, the inclusion of the scienter requirements does not resolve the undue burden concerns recognized by the Supreme Court in Stenberg. Hi. Conclusion The Act’s definition of the prohibited procedure, like that of the unconstitutional Nebraska statute, covers both forms of D & E, intact and non-intact. In any event, it fails to differentiate between the two sufficiently clearly to permit doctors to perform the latter procedure without fear of prosecution. Because the Act applies to, or could readily be employed to prosecute, physicians who “use [non-intaet] D & E procedures, the most commonly used method for performing previability second trimester abortions,” Stenberg, 530 U.S. at 945, 120 S.Ct. 2597, it imposes a substantial risk of criminal liability on almost all doctors who perform previability abortions after the first trimester. Thus, the Act would, at a minimum, create a chilling effect that “ ‘plac[es] a substantial obstacle in the path of a woman seeking an abortion of a nonviable fetus.’ ” Id. at 921, 120 S.Ct. 2597. We conclude that, because of both the actual and the potential risk to doctors who perform previability abortions, the Act imposes an “undue burden upon a woman’s right to make an abortion decision,” id. at 946, 120 S.Ct. 2597, and is unconstitutional. C. The Act is Unconstitutionally Vague Besides lacking the required health exception and imposing an undue burden on a woman’s right to terminate her pregnancy, the Act is also unconstitutionally vague. It fails to define clearly the medical procedures it prohibits, depriving doctors of fair notice and encouraging arbitrary enforcement. The Act’s scienter requirements do not cure the statute’s vagueness. We conclude that the Act’s unconstitutional vagueness constitutes an independent ground for affirming the district court’s finding of unconstitutionality. To survive vagueness review, a statute must “(1) define the offense with sufficient definiteness that ordinary people can understand what conduct is prohibited; and (2) establish standards to permit police to enforce the law in a non-arbitrary, nondiscriminatory manner.” Nunez by Nunez v. City of San Diego, 114 F.3d 935, 940 (9th Cir.1997) (citing Kolender v. Lawson, 461 U.S. 352, 357, 103 S.Ct. 1855, 75 L.Ed.2d 903 (1983)). The need to avoid vagueness is particularly acute when the statute imposes criminal penalties, see Forbes v. Napolitano, 236 F.3d 1009, 1011-12 (9th Cir.2000) (as amended), or when it implicates constitutionally protected rights, see Nunez by Nunez, 114 F.3d at 940. Because this statute both imposes criminal penalties and implicates a constitutionally protected right, it is subject to heightened vagueness review. Id. The Act cannot survive that review. The government essentially makes three arguments regarding the vagueness of the Act. First, it asserts that the statutory scheme as a whole “specifically and narrowly defines” the single “method of abortion” that it outlaws (i.e., intact D & E). As we have explained, Stenberg explicitly described, for the benefit of legislative bodies (and, presumably, the government), two possible ways to make clear that a prohibition on intact D & E is applicable only to that form of the procedure. Congress deliberately declined to adopt either method and instead drafted statutory language that may best be understood as also outlawing non-intact D & Es, the type of procedure most often used to perform post-first trimester previability abortions. This reading of the statute was confirmed by the trial testimony of numerous doctors and practitioners offering abortion services. As the district court noted, “they do not understand exactly what the Act prohibits.” Planned Parenthood, 320 F.Supp.2d at 977. Although we may conclude following a painstaking legal analysis that the statute covers both forms of D & E, the language of the statute, taken as a whole, is not sufficiently clear regarding what it permits and prohibits to guide the conduct of those affected by it terms, specifically medical practitioners. As a result, the Act is unconstitutionally vague, and certainly so if the legislative intent was, as the government argues, to restrict its scope to intact D & E. Second, the government objects to the district court’s conclusion that the specific terms “partial-birth abortion,” “overt act,” and “living fetus” are “fatally ambiguous.” As to the term “partial-birth abortion,” the government challenges the district court’s statement that the term has “little if any medical significance,” arguing that it is “ ‘widely known’ as synonymous with the medical terms ‘D & X’ and ‘intact D & E.’ ” The only citation the government offers to support this argument is a Sixth Circuit case, Women’s Med. Prof'l Corp. v. Taft, 353 F.3d 436, 439-40 (6th Cir.2003), which considered an Ohio ban on “partial-birth abortion.” Taft, however, does nothing to bolster the government’s argument that the term “partial-birth abortion” is, in and of itself, sufficiently clear as to the procedures it encompasses that any vagueness problems with the statute are cured. In fact, the contrast between the Ohio statute reviewed in Taft and the federal Act at issue here illuminates the latter’s vagueness. In Taft, the Sixth Circuit's conclusion that the Ohio statute survived vagueness review did not rest at all on the proposition that the term “partial-birth abortion” is “ ‘widely known’ as synonymous with the medical terms ‘D & X’ and ‘intact D & E.’” Rather, the Sixth Circuit held the Ohio law was not unconstitutionally vague because the statute defined the restricted procedures using “clinical terms” and explicitly stated that it did not apply to non-intact D & E or other abortion procedures besides intact D & E. Taft, 353 F.3d at 441. The Sixth Circuit noted that by defining the reach of its statute’s prohibition in this way, Ohio heeded the Supreme Court’s observation in Stenberg that “Nebraska might have fared better if its description of the procedure had ‘tracked the medical differences between [non-intact] D & E and [intact D & E],’ [or] ‘provided an exception for the performance of [non-intact] D & E and other abortion procedures.’ ” Taft, 353 F.3d at 452 (quoting Stenberg, 530 U.S. at 939, 120 S.Ct. 2597). By contrast, Congress chose to ignore Stenberg’s warning when it enacted the Act, as noted in the previous section, and failed to follow its clear roadmap — either by defining the scope of the statute’s prohibition using clinical terms that track the medical differences between intact D & E and other forms of D & E or by delineating expressly which procedures are exempted from the ban. The Taft decision, therefore, provides no support for the proposition that the term “partial-birth abortion” is concrete enough on its own to obviate any vagueness concerns with a statute that seeks to outlaw it. The government cites no other case, in this circuit or any other, that supports its proposition and thus has offered no justification for its claim that “partial-birth abortion,” which is not a recognized medical term, is itself sufficiently clear to overcome the vagueness concerns identified by the district court. Alternatively, the government argues that “partial-birth abortion” is an “expressly defined term [in the statute] ... and thus cannot itself support a vagueness challenge.” However, the mere fact that “partial-birth abortion” is an “expressly defined term” in the statute is not enough to survive vagueness review if that definition is itself vague, as is the case here. See, e.g., Planned Parenthood of Cent N.J. v. Farmer, 220 F.3d 127, 136-40 (3d Cir.2000) (finding a New Jersey statute outlawing “partial-birth abortion” unconstitutional based on its conclusion that its definition of “partial-birth abortion” was vague). Although the federal Act uses somewhat different language from that used in the statute invalidated in Stenberg, its definition of “partial-birth abortion” nonetheless “fails to provide a reasonable opportunity to know what conduct is prohibited” and “is so indefinite as to allow arbitrary and discriminatory enforcement.” Tucson Woman’s Clinic, 379 F.3d at 554. The Act does not “specifically and narrowly define! ]” a single “method of abortion,” as the government claims; rather, its provisions could readily be applied to a range of methods of performing post-first trimester abortions. Furthermore, as discussed above, Congress chose not to take the simple steps, suggested by the Court in Stenberg, to cure the vagueness in its definition of partial-birth abortion. As a result, doctors who perform non-intact D & E abortions, which the government contends are not intended to be outlawed by the Act, have good reason to fear that they will be deemed subject to its prohibitions. At the least, they cannot be reasonably certain that their conduct is beyond the reach of the Act’s criminal provisions; nor can they be reasonably assured that the Act will not be arbitrarily enforced. The government also objects to the district court’s characterization of “overt act” as vague. It asserts that the term itself is not unconstitutionally vague, citing its use in the Constitution and various federal statutes. It further claims that by modifying “overt act” with the phrase “other than completion of delivery,” the statute makes clear that the term does not apply to “cutting the umbilical cord” or other “essential aspects of delivery,” which, it argues, establishes that the statute’s ban does not encompass induction. While the government rightly points out that the term “overt act” is not in all usages unconstitutionally vague, the district court was correct to hold that in the context of the Act it is, even when modified by “other than completion of delivery.” Beyond concluso-ry statements, the government in no way refutes the district court’s determination that “overt act, other than completion of delivery” can plausibly encompass a range of acts involved in non-intact D & E, including disarticulation and compressing or decompressing the skull or abdomen or other fetal part that is obstructing completion of the uterine evacuation (and in induction, possibly even the cutting of the umbilical cord). Because these acts can readily be deemed covered by the phrase “overt act, other than completion of delivery,” the phrase does not provide the definitiveness about the statute’s scope that the government asserts. The use of the term “overt act” does nothing to remedy the statute’s failure to provide adequate notice of what forms of D & E the Act prohibits and to prevent its arbitrary enforcement. See Forbes, 236 F.3d at 1011. The government additionally challenges the district court’s conclusion that the term “living fetus” contributes to the vagueness of the statute. We, like the Third Circuit, conclude that the use of “living fetus” in a statute banning “partial-birth abortions” adds to confusion about the scope of the prohibited conduct. Although the term “living fetus” may suggest to some that the Act’s prohibition is limited to abortions of viable fetuses, the term has no such meaning. While a fetus typically is not viable until at least 24 weeks Imp, it can be “living” — meaning that it has a detectable heartbeat or pulsating umbilical cord — as early as seven weeks Imp, well before the end of even the first trimester. As the Third Circuit noted, “because a fetus may be ‘living’ as early as seven weeks Imp, use of the term ‘living’ instead of ‘viable’ indicates that, contrary to the understanding of a large segment of the public and the concomitant rhetoric, the Act is in no way limited to late-term, or even mid-term, abortions.... [M]ost common abortion procedures will fall within this limitation.” Farmer, 220 F.3d at 137. Therefore, far from curing the statute’s vagueness problems, the use of the term “living fetus” instead of “viable fetus” creates additional confusion about the Act’s scope. Third, the government argues that any unconstitutional vagueness is eliminated by the “narrowing and mutually reinforcing scienter requirements.” However, as we explained in the undue burden section, section III.B supra, the scienter requirements do not restrict the statute’s reach to doctors who purposely set out to perform the intact form of the D & E procedure. They therefore do not remedy the Act’s failure to provide fair warning of the prohibited conduct; rather, they permit the Act’s arbitrary and discriminatory enforcement. In short, as we recently held, a scienter requirement applied to an element that is itself vague does not cure the provision’s overall vagueness. See Wasden, 376 F.3d at 933; see also Farmer, 220 F.3d at 138 (“At a minimum, to limit the scope of a statute to ‘deliberately and intentionally’ performing a certain procedure, the procedure itself must be identified or readily susceptible of identification. Here, it is not.” (citations omitted)); Planned Parenthood of Greater Iowa, Inc. v. Miller, 195 F.3d 386, 389 (8th Cir.1999) (holding that Iowa partial-birth abortion ban’s inclusion of scienter requirement “cannot save it” because the Act still “encompasses more than just the [intact D & E] procedure”); R.I. Med. Soc’y v. Whitehouse, 66 F.Supp.2d 288, 311-12 (D.R.I. 1999) (holding that scienter requirement could not save Rhode Island’s partial birth abortion statute because the “scienter requirement modifies a vague term”). The scienter requirements, therefore, do nothing to cure the Act’s vagueness. Because neither the statute when read as a whole nor its individual components provide fair warning of the prohibited conduct to those it regulates and because the Act permits arbitrary and discriminatory enforcement, we affirm the district court's determination that the Act is unconstitutionally vague. IV. Remedy In considering the remedy for a statute found to restrict access to abortion in violation of the Constitution, we are guided by “[tjhree interrelated principles.” Ayotte, at 967. First, we endeavor to invalidate no more of a statute than necessary. Id. Second, “mindful that our constitutional mandate and institutional competence are limited, we restrain ourselves from ‘rewriting] state law to conform it to constitutional requirements’ even as we strive to salvage it.” Id. (quoting Virginia v. Am. Booksellers Ass’n, 484 U.S. 383, 397, 108 S.Ct. 636, 98 L.Ed.2d 782 (1988)). Third, in devising the remedy we must be cognizant of legislative intent “for a court cannot ‘use its remedial powers to circumvent the intent of the legislature.’ ” Ayotte, at 967 (quoting Califano v. Westcott, 443 U.S. 76, 94, 99 S.Ct. 2655, 61 L.Ed.2d 382 (1979) (Powell, J., concurring in part and dissenting in part)). Applying these principles to the present case, we conclude that upholding the permanent injunction against the enforcement of the statute in its entirety is the only permissible remedy. We cannot, consistent with the judiciary’s limited role, devise a narrower injunction that adequately addresses the various constitutional infirmities in the Act. Our conclusion is dictated in part by the grounds on which we hold the Act unconstitutional. We do not conclude that it is unconstitutional solely due to its lack of a health exception. Cf. Ayotte, at 965 (“We granted certiorari to decide whether the courts below erred in invalidating the Act in its entirety because it lacks an exception for the preservation of pregnant minors’ health.” (internal citation omitted)). Had our holding on the statute’s constitutionality rested solely on that ground, we might have been able to draft a more “finely drawn” injunction, Ayotte, at 969, prohibiting the Act’s enforcement only when the banned procedure was necessary to preserve a woman’s health. Because such relief would not requir