FDA v. Alliance for Hippocratic Medicine (2024)

(Slip Opinion) OCTOBER TERM, 2023 1 Syllabus NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337 . SUPREME COURT OF THE UNITED STATES Syllabus FOOD AND DRUG ADMINISTRATION ET AL. v. ALLIANCE FOR HIPPOCRATIC MEDICINE ET AL. CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIFTH CIRCUIT No. 23–235. Argued March 26, 2024—Decided June 13, 2024* In 2000, the Food and Drug Administration approved a new drug application for mifepristone tablets marketed under the brand name Mifeprex for use in terminating pregnancies up to seven weeks. To help ensure that Mifeprex would be used safely and effectively, FDA placed additional restrictions on the drug’s use and distribution, for example requiring doctors to prescribe or to supervise prescription of Mifeprex, and requiring patients to have three in-person visits with the doctor to receive the drug. In 2016, FDA relaxed some of these restrictions: deeming Mifeprex safe to terminate pregnancies up to 10 weeks; allowing healthcare providers, such as nurse practitioners, to prescribe Mifeprex; and approving a dosing regimen that required just one in-person visit to receive the drug. In 2019, FDA approved an application for generic mifepristone. In 2021, FDA announced that it would no longer enforce the initial in-person visit requirement. Four pro-life medical associations and several individual doctors moved for a preliminary injunction that would require FDA either to rescind approval of mifepristone or to rescind FDA’s 2016 and 2021 regulatory actions. Danco Laboratories, which sponsors Mifeprex, intervened to defend FDA’s actions. The District Court agreed with the plaintiffs and in effect enjoined FDA’s approval of mifepristone, thereby ordering mifepristone off the market. FDA and Danco appealed and moved to stay the District Court’s order pending appeal. As relevant here, this Court ultimately —————— *Together with No. 23–236, Danco Laboratories, L.L.C. v. Alliance for Hippocratic Medicine, also on certiorari to the United States Court of Appeals for the Fifth Circuit. 2 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Syllabus stayed the District Court’s order pending the disposition of proceedings in the Fifth Circuit and this Court. On the merits, the Fifth Circuit held that plaintiffs had standing. It concluded that plaintiffs were unlikely to succeed on their challenge to FDA’s 2000 and 2019 drug approvals, but were likely to succeed in showing that FDA’s 2016 and 2021 actions were unlawful. This Court granted certiorari with respect to the 2016 and 2021 FDA actions. Held: Plaintiffs lack Article III standing to challenge FDA’s actions regarding the regulation of mifepristone. Pp. 5–25. (a) Article III standing is a “bedrock constitutional requirement that this Court has applied to all manner of important disputes.” United States v. Texas, 599 U. S. 670, 675 . Standing is “built on a single basic idea—the idea of separation of powers.” Ibid. Article III confines the jurisdiction of federal courts to “Cases” and “Controversies.” Federal courts do not operate as an open forum for citizens “to press general complaints about the way in which government goes about its business.” Allen v. Wright, 468 U. S. 737, 760 . To obtain a judicial determination of what the governing law is, a plaintiff must have a “personal stake” in the dispute. TransUnion LLC v. Ramirez, 594 U. S. 413, 423 . To establish standing, a plaintiff must demonstrate (i) that she has suffered or likely will suffer an injury in fact, (ii) that the injury likely was caused or will be caused by the defendant, and (iii) that the injury likely would be redressed by the requested judicial relief. See Summers v. Earth Island Institute, 555 U. S. 488, 493 . The two key questions in most standing disputes are injury in fact and causation. By requiring the plaintiff to show an injury in fact, Article III standing screens out plaintiffs who might have only a general legal, moral, ideological, or policy objection to a particular government action. Causation requires the plaintiff to establish that the plaintiff ’s injury likely was caused or likely will be caused by the defendant’s conduct. Causation is “ordinarily substantially more difficult to establish” when (as here) a plaintiff challenges the government’s “unlawful regulation (or lack of regulation) of someone else.” Lujan v. Defenders of Wildlife, 504 U. S. 555 , 560–561. That is because unregulated parties often may have more difficulty linking their asserted injuries to the government’s regulation (or lack of regulation) of someone else. Pp. 5–12. (b) Plaintiffs are pro-life, oppose elective abortion, and have sincere legal, moral, ideological, and policy objections to mifepristone being prescribed and used by others. Because plaintiffs do not prescribe or use mifepristone, plaintiffs are unregulated parties who seek to challenge FDA’s regulation of others. Plaintiffs advance several complicated causation theories to connect FDA’s actions to the plaintiffs’ alleged injuries in fact. None of these theories suffices to Cite as: 602 U. S. ____ (2024) 3 Syllabus establish Article III standing. Pp. 13–24. (1) Plaintiffs first contend that FDA’s relaxed regulation of mifepristone may cause downstream conscience injuries to the individual doctors. Even assuming that FDA’s 2016 and 2021 changes to mifepristone’s conditions of use cause more pregnant women to require emergency abortions and that some women would likely seek treatment from these plaintiff doctors, the plaintiff doctors have not shown that they could be forced to participate in an abortion or provide abortion-related medical treatment over their conscience objections. Federal conscience laws definitively protect doctors from being required to perform abortions or to provide other treatment that violates their consciences. Federal law protects doctors from repercussions when they have “refused” to participate in an abortion. §300a–7(c)(1). The plaintiffs have not identified any instances where a doctor was required, notwithstanding conscience objections, to perform an abortion or to provide other abortion-related treatment that violated the doctor’s conscience since mifepristone’s 2000 approval. Further, the Emergency Medical Treatment and Labor Act (or EMTALA) neither overrides federal conscience laws nor requires individual emergency room doctors to participate in emergency abortions. Thus, there is a break in any chain of causation between FDA’s relaxed regulation of mifepristone and any asserted conscience injuries to the doctors. Pp. 14–17. (2) Plaintiffs next assert they have standing because FDA’s relaxed regulation of mifepristone may cause downstream economic injuries to the doctors. The doctors cite various monetary and related injuries that they will allegedly suffer as a result of FDA’s actions—in particular, diverting resources and time from other patients to treat patients with mifepristone complications; increasing risk of liability suits from treating those patients; and potentially increasing insurance costs. But the causal link between FDA’s regulatory actions in 2016 and 2021 and those alleged injuries is too speculative, lacks support in the record, and is otherwise too attenuated to establish standing. Moreover, the law has never permitted doctors to challenge the government’s loosening of general public safety requirements simply because more individuals might then show up at emergency rooms or in doctors’ offices with follow-on injuries. Citizens and doctors who object to what the law allows others to do may always take their concerns to the Executive and Legislative Branches and seek greater regulatory or legislative restrictions. Pp. 18–21. (3) Plaintiff medical associations assert their own organizational standing. Under the Court’s precedents, organizations may have standing “to sue on their own behalf for injuries they have sustained,” Havens Realty Corp. v. Coleman, 455 U. S. 363, 379, n. 19 , but 4 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Syllabus organizations must satisfy the usual standards for injury in fact, causation, and redressability that apply to individuals, id., at 378–379. According to the medical associations, FDA has “impaired” their “ability to provide services and achieve their organizational missions.” Brief for Respondents 43. That argument does not work to demonstrate standing. Like an individual, an organization may not establish standing simply based on the “intensity of the litigant’s interest” or because of strong opposition to the government’s conduct, Valley Forge Christian College v. Americans United for Separation of Church and State, Inc., 454 U. S. 464, 486 . The plaintiff associations therefore cannot establish standing simply because they object to FDA’s actions. The medical associations claim to have standing based on their incurring costs to oppose FDA’s actions. They say that FDA has “caused” the associations to conduct their own studies on mifepristone so that the associations can better inform their members and the public about mifepristone’s risks. Brief for Respondents 43. They contend that FDA has “forced” the associations to “expend considerable time, energy, and resources” drafting citizen petitions to FDA, as well as engaging in public advocacy and public education, all to the detriment of other spending priorities. Id., at 44. But an organization that has not suffered a concrete injury caused by a defendant’s action cannot spend its way into standing simply by expending money to gather information and advocate against the defendant’s action. Contrary to what the medical associations contend, the Court’s decision in Havens Realty Corp. v. Coleman does not stand for the expansive theory that standing exists when an organization diverts its resources in response to a defendant’s actions. Havens was an unusual case, and this Court has been careful not to extend the Havens holding beyond its context. So too here. Finally, it was suggested that plaintiffs must have standing because otherwise it may be that no one would have standing to challenge FDA’s 2016 and 2021 actions. That suggestion fails because the Court has long rejected that kind of argument as a basis for standing. The “assumption” that if these plaintiffs lack “standing to sue, no one would have standing, is not a reason to find standing.” Schlesinger v. Reservists Comm. to Stop the War, 418 U. S. 208, 227 . Rather, some issues may be left to the political and democratic processes. Pp. 21– 24. 78 F. 4th 210 , reversed and remanded. KAVANAUGH, J., delivered the opinion for a unanimous Court. THOMAS, J., filed a concurring opinion. Cite as: 602 U. S. ____ (2024) 1 Opinion of the Court NOTICE: This opinion is subject to formal revision before publication in the United States Reports. Readers are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, [email protected], of any typographical or other formal errors. SUPREME COURT OF THE UNITED STATES _________________ Nos. 23–235 and 23–236 _________________ FOOD AND DRUG ADMINISTRATION, ET AL., PETITIONERS 23–235 v. ALLIANCE FOR HIPPOCRATIC MEDICINE, ET AL. DANCO LABORATORIES, L.L.C., PETITIONER 23–236 v. ALLIANCE FOR HIPPOCRATIC MEDICINE, ET AL. ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIFTH CIRCUIT [June 13, 2024] JUSTICE KAVANAUGH delivered the opinion of the Court. In 2016 and 2021, the Food and Drug Administration relaxed its regulatory requirements for mifepristone, an abortion drug. Those changes made it easier for doctors to prescribe and pregnant women to obtain mifepristone. Several pro-life doctors and associations sued FDA, arguing that FDA’s actions violated the Administrative Procedure Act. But the plaintiffs do not prescribe or use mifepristone. And FDA is not requiring them to do or refrain from doing anything. Rather, the plaintiffs want FDA to make mifepristone more difficult for other doctors to prescribe and for pregnant women to obtain. Under Article III of the Constitution, a plaintiff ’s desire to make a drug less available for others does not establish standing to sue. Nor do the plaintiffs’ other standing theories suffice. Therefore, the plaintiffs lack standing to challenge FDA’s actions. 2 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Opinion of the Court I A Under federal law, the U. S. Food and Drug Administration, an agency within the Executive Branch, ensures that drugs on the market are safe and effective. For FDA to approve a new drug, the drug sponsor (usually the drug’s manufacturer or potential marketer) must submit an application demonstrating that the drug is safe and effective when used as directed. 21 U. S. C. §355 (d). The sponsor’s application must generally include proposed labeling that specifies the drug’s dosage, how to take the drug, and the specific conditions that the drug may treat. 21 CFR §§201.5 , 314.50 (2022). If FDA determines that additional safety requirements are necessary, FDA may impose extra requirements on prescription and use of the drug. 21 U. S. C. §355–1(f )(3). For example, FDA may require that prescribers undergo specialized training; mandate that the drug be dispensed only in certain settings like hospitals; or direct that doctors monitor patients taking the drug. Ibid. In 2000, FDA approved a new drug application for mifepristone tablets marketed under the brand name Mifeprex. FDA approved Mifeprex for use to terminate pregnancies, but only up to seven weeks of pregnancy. To help ensure that Mifeprex would be used safely and effectively, FDA placed further restrictions on the drug’s use and distribution. For example, only doctors could prescribe or supervise prescription of Mifeprex. Doctors and patients also had to follow a strict regimen requiring the patient to appear for three in-person visits with the doctor. And FDA directed prescribing doctors to report incidents of hospitalizations, blood transfusions, or other serious adverse events to the drug sponsor (who, in turn, was required to report the events to FDA). In 2015, Mifeprex’s distributor Danco Laboratories submitted a supplemental new drug application seeking to Cite as: 602 U. S. ____ (2024) 3 Opinion of the Court amend Mifeprex’s labeling and to relax some of the restrictions that FDA had imposed. In 2016, FDA approved the proposed changes. FDA deemed Mifeprex safe to terminate pregnancies up to 10 weeks rather than 7 weeks. FDA allowed healthcare providers such as nurse practitioners to prescribe Mifeprex. And FDA approved a dosing regimen that reduced the number of required in- person visits from three to one—a single visit to receive Mifeprex. In addition, FDA changed prescribers’ adverse event reporting obligations to require prescribers to report only fatalities—a reporting requirement that was still more stringent than the requirements for most other drugs. In 2019, FDA approved an application for generic mifepristone. FDA established the same conditions of use for generic mifepristone as for Mifeprex. In 2021, FDA again relaxed the requirements for Mifeprex and generic mifepristone. Relying on experience gained during the COVID–19 pandemic about pregnant women using mifepristone without an in-person visit to a healthcare provider, FDA announced that it would no longer enforce the initial in-person visit requirement. B Because mifepristone is used to terminate pregnancies, FDA’s approval and regulation of mifepristone have generated substantial controversy from the start. In 2002, three pro-life associations submitted a joint citizen petition asking FDA to rescind its approval of Mifeprex. FDA denied their petition. In 2019, two pro-life medical associations filed another petition, this time asking FDA to withdraw its 2016 modifications to mifepristone’s conditions of use. FDA denied that petition as well. This case began in 2022. Four pro-life medical associations, as well as several individual doctors, sued FDA in the U. S. District Court for the Northern District of 4 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Opinion of the Court Texas. Plaintiffs brought claims under the Administrative Procedure Act. They challenged the lawfulness of FDA’s 2000 approval of Mifeprex; FDA’s 2019 approval of generic mifepristone; and FDA’s 2016 and 2021 actions modifying mifepristone’s conditions of use. Danco Laboratories, which sponsors Mifeprex, intervened to defend FDA’s actions. The plaintiffs moved for a preliminary injunction that would require FDA to rescind approval of mifepristone or, at the very least, to rescind FDA’s 2016 and 2021 actions. The District Court agreed with the plaintiffs and in effect enjoined FDA’s approval of mifepristone, thereby ordering mifepristone off the market. 668 F. Supp. 3d 507 (ND Tex. 2023). The court first held that the plaintiffs possessed Article III standing. It then determined that the plaintiffs were likely to succeed on the merits of each of their claims. Finally, the court concluded that the plaintiffs would suffer irreparable harm from FDA’s continued approval of mifepristone and that an injunction would serve the public interest. FDA and Danco promptly appealed and moved to stay the District Court’s order pending appeal. The U. S. Court of Appeals for the Fifth Circuit granted the stay motion in part and temporarily reinstated FDA’s approval of Mifeprex. 2023 WL 2913725 , *21 (Apr. 12, 2023). But the Court of Appeals declined to stay the rest of the District Court’s order. The Court of Appeals’ partial stay would have left Mifeprex (though not generic mifepristone) on the market, but only under the more stringent requirements imposed when FDA first approved Mifeprex in 2000— available only up to seven weeks of pregnancy, only when prescribed by doctors, and only with three in-person visits, among other requirements. FDA and Danco then sought a full stay in this Court. This Court stayed the District Court’s order in its entirety pending the disposition of FDA’s and Danco’s appeals in the Court of Appeals and ultimate resolution by this Court. 598 Cite as: 602 U. S. ____ (2024) 5 Opinion of the Court U. S. ___ (2023). As a result of this Court’s stay, Mifeprex and generic mifepristone have remained available as allowed by FDA’s relaxed 2016 and 2021 requirements. A few months later, the Court of Appeals issued its decision on the merits of the District Court’s order, affirming in part and vacating in part. 78 F. 4th 210 , 222– 223 (CA5 2023). The Court of Appeals first concluded that the individual doctors and the pro-life medical associations had standing. The Court of Appeals next concluded that plaintiffs were not likely to succeed on their challenge to FDA’s 2000 approval of Mifeprex and 2019 approval of generic mifepristone. So the Court of Appeals vacated the District Court’s order as to those agency actions. But the Court of Appeals agreed with the District Court that plaintiffs were likely to succeed in showing that FDA’s 2016 and 2021 actions were unlawful. The Court of Appeals’ merits decision did not alter this Court’s stay of the District Court’s order pending this Court’s review. This Court then granted certiorari with respect to the 2016 and 2021 FDA actions held unlawful by the Court of Appeals. 601 U. S. ___ (2023). II The threshold question is whether the plaintiffs have standing to sue under Article III of the Constitution. Article III standing is a “bedrock constitutional requirement that this Court has applied to all manner of important disputes.” United States v. Texas, 599 U. S. 670, 675 (2023). Standing is “built on a single basic idea—the idea of separation of powers.” Ibid. (quotation marks omitted). Importantly, separation of powers “was not simply an abstract generalization in the minds of the Framers: it was woven into the document that they drafted in Philadelphia in the summer of 1787.” TransUnion LLC v. Ramirez, 594 U. S. 413 , 422–423 (2021) (quotation marks omitted). Therefore, we begin as always with the precise 6 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Opinion of the Court text of the Constitution. Article III of the Constitution confines the jurisdiction of federal courts to “Cases” and “Controversies.” The case or controversy requirement limits the role of the Federal Judiciary in our system of separated powers. As this Court explained to President George Washington in 1793 in response to his request for a legal opinion, federal courts do not issue advisory opinions about the law—even when requested by the President. 13 Papers of George Washington: Presidential Series 392 (C. Patrick ed. 2007). Nor do federal courts operate as an open forum for citizens “to press general complaints about the way in which government goes about its business.” Allen v. Wright, 468 U. S. 737, 760 (1984) (quotation marks omitted); see California v. Texas, 593 U. S. 659, 673 (2021); Valley Forge Christian College v. Americans United for Separation of Church and State, Inc., 454 U. S. 464, 487 (1982); United States v. Richardson, 418 U. S. 166, 175 (1974); Ex parte Levitt, 302 U. S. 633 , 634 (1937) (per curiam); Massachusetts v. Mellon, 262 U. S. 447 , 487–488 (1923); Fairchild v. Hughes, 258 U. S. 126 , 129–130 (1922). As Justice Scalia memorably said, Article III requires a plaintiff to first answer a basic question: “ ‘What’s it to you?’ ” A. Scalia, The Doctrine of Standing as an Essential Element of the Separation of Powers, 17 Suffolk U. L. Rev. 881 , 882 (1983). For a plaintiff to get in the federal courthouse door and obtain a judicial determination of what the governing law is, the plaintiff cannot be a mere bystander, but instead must have a “personal stake” in the dispute. TransUnion, 594 U. S., at 423 . The requirement that the plaintiff possess a personal stake helps ensure that courts decide litigants’ legal rights in specific cases, as Article III requires, and that courts do not opine on legal issues in response to citizens who might “roam the country in search of governmental wrongdoing.” Valley Forge, 454 U. S., at 487 ; see, e.g., Schlesinger v. Reservists Comm. to Cite as: 602 U. S. ____ (2024) 7 Opinion of the Court Stop the War, 418 U. S. 208, 227 (1974); Richardson, 418 U. S., at 175 ; Tyler v. Judges of Court of Registration, 179 U. S. 405, 406 (1900). Standing also “tends to assure that the legal questions presented to the court will be resolved, not in the rarified atmosphere of a debating society, but in a concrete factual context conducive to a realistic appreciation of the consequences of judicial action.” Valley Forge, 454 U. S., at 472 . Moreover, the standing doctrine serves to protect the “autonomy” of those who are most directly affected so that they can decide whether and how to challenge the defendant’s action. Id., at 473 . By limiting who can sue, the standing requirement implements “the Framers’ concept of the proper—and properly limited—role of the courts in a democratic society.” J. Roberts, Article III Limits on Statutory Standing, 42 Duke L. J. 1219, 1220 (1993) (quotation marks omitted). In particular, the standing requirement means that the federal courts decide some contested legal questions later rather than sooner, thereby allowing issues to percolate and potentially be resolved by the political branches in the democratic process. See Raines v. Byrd, 521 U. S. 811 , 829– 830 (1997); cf. Clapper v. Amnesty Int’l USA, 568 U. S. 398 , 420–422 (2013). And the standing requirement means that the federal courts may never need to decide some contested legal questions: “Our system of government leaves many crucial decisions to the political processes,” where democratic debate can occur and a wide variety of interests and views can be weighed. Schlesinger, 418 U. S., at 227 ; see Campbell v. Clinton, 203 F. 3d 19, 23 (CADC 2000). A The fundamentals of standing are well-known and firmly rooted in American constitutional law. To establish standing, as this Court has often stated, a plaintiff must demonstrate (i) that she has suffered or likely will suffer an injury in fact, (ii) that the injury likely was caused or will 8 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Opinion of the Court be caused by the defendant, and (iii) that the injury likely would be redressed by the requested judicial relief. See Summers v. Earth Island Institute, 555 U. S. 488, 493 (2009); Lujan v. Defenders of Wildlife, 504 U. S. 555 , 560– 561 (1992). Those specific standing requirements constitute “an essential and unchanging part of the case-or- controversy requirement of Article III.” Id., at 560 . The second and third standing requirements—causation and redressability—are often “flip sides of the same coin.” Sprint Communications Co. v. APCC Services, Inc., 554 U. S. 269, 288 (2008). If a defendant’s action causes an injury, enjoining the action or awarding damages for the action will typically redress that injury. So the two key questions in most standing disputes are injury in fact and causation.1 First is injury in fact. An injury in fact must be “concrete,” meaning that it must be real and not abstract. See TransUnion, 594 U. S., at 424 . The injury also must be particularized; the injury must affect “the plaintiff in a personal and individual way” and not be a generalized grievance. Lujan, 504 U. S., at 560, n. 1 . An injury in fact can be a physical injury, a monetary injury, an injury to one’s property, or an injury to one’s constitutional rights, to take just a few common examples. Moreover, the injury must be actual or imminent, not speculative—meaning that the injury must have already occurred or be likely to occur soon. Clapper, 568 U. S., at 409 . And when a plaintiff seeks prospective relief such as an injunction, the plaintiff must establish a sufficient likelihood of future injury. Id., at 401 . By requiring the plaintiff to show an injury in fact, Article —————— 1 Redressability can still pose an independent bar in some cases. For example, a plaintiff who suffers injuries caused by the government still may not be able to sue because the case may not be of the kind “traditionally redressable in federal court.” United States v. Texas, 599 U. S. 670, 676 (2023); cf. California v. Texas, 593 U. S. 659 , 671–672 (2021). Cite as: 602 U. S. ____ (2024) 9 Opinion of the Court III standing screens out plaintiffs who might have only a general legal, moral, ideological, or policy objection to a particular government action. For example, a citizen does not have standing to challenge a government regulation simply because the plaintiff believes that the government is acting illegally. See Valley Forge, 454 U. S., at 473, 487 . A citizen may not sue based only on an “asserted right to have the Government act in accordance with law.” Allen, 468 U. S., at 754 ; Schlesinger, 418 U. S., at 225–227. Nor may citizens sue merely because their legal objection is accompanied by a strong moral, ideological, or policy objection to a government action. See Valley Forge, 454 U. S., at 473 . The injury in fact requirement prevents the federal courts from becoming a “vehicle for the vindication of the value interests of concerned bystanders.” Allen, 468 U. S., at 756 (quotation marks omitted). An Article III court is not a legislative assembly, a town square, or a faculty lounge. Article III does not contemplate a system where 330 million citizens can come to federal court whenever they believe that the government is acting contrary to the Constitution or other federal law. See id., at 754 . Vindicating “the public interest (including the public interest in Government observance of the Constitution and laws) is the function of Congress and the Chief Executive.” Lujan, 504 U. S., at 576 . In sum, to sue in federal court, a plaintiff must show that he or she has suffered or likely will suffer an injury in fact. Second is causation. The plaintiff must also establish that the plaintiff ’s injury likely was caused or likely will be caused by the defendant’s conduct. Government regulations that require or forbid some action by the plaintiff almost invariably satisfy both the injury in fact and causation requirements. So in those cases, standing is usually easy to establish. See Lujan, 504 U. S., at 561–562; see, e.g., Susan B. Anthony List v. 10 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Opinion of the Court Driehaus, 573 U. S. 149 , 162–163 (2014). By contrast, when (as here) a plaintiff challenges the government’s “unlawful regulation (or lack of regulation) of someone else,” “standing is not precluded, but it is ordinarily substantially more difficult to establish.” Lujan, 504 U. S., at 562 (quotation marks omitted); see Summers, 555 U. S., at 493 . That is often because unregulated parties may have more difficulty establishing causation—that is, linking their asserted injuries to the government’s regulation (or lack of regulation) of someone else. See Clapper, 568 U. S., at 413–414; Lujan, 504 U. S., at 562 ; Duke Power Co. v. Carolina Environmental Study Group, Inc., 438 U. S. 59, 74 (1978); Simon v. Eastern Ky. Welfare Rights Organization, 426 U. S. 26 , 41–46 (1976); Warth v. Seldin, 422 U. S. 490 , 504–508 (1975). When the plaintiff is an unregulated party, causation “ordinarily hinge[s] on the response of the regulated (or regulable) third party to the government action or inaction—and perhaps on the response of others as well.” Lujan, 504 U. S., at 562 . Yet the Court has said that plaintiffs attempting to show causation generally cannot “rely on speculation about the unfettered choices made by independent actors not before the courts.” Clapper, 568 U. S., at 415, n. 5 (quotation marks omitted); see also Bennett v. Spear, 520 U. S. 154 , 168–169 (1997). Therefore, to thread the causation needle in those circumstances, the plaintiff must show that the “ ‘third parties will likely react in predictable ways’ ” that in turn will likely injure the plaintiffs. California, 593 U. S., at 675 (quoting Department of Commerce v. New York, 588 U. S. 752, 768 (2019)). As this Court has explained, the “line of causation between the illegal conduct and injury”—the “links in the chain of causation,” Allen, 468 U. S., at 752 , 759—must not be too speculative or too attenuated, Clapper, 568 U. S., at 410–411. The causation requirement precludes speculative Cite as: 602 U. S. ____ (2024) 11 Opinion of the Court links—that is, where it is not sufficiently predictable how third parties would react to government action or cause downstream injury to plaintiffs. See Allen, 468 U. S., at 757–759; Simon, 426 U. S., at 41–46. The causation requirement also rules out attenuated links—that is, where the government action is so far removed from its distant (even if predictable) ripple effects that the plaintiffs cannot establish Article III standing. See Allen, 468 U. S., at 757– 759; cf. Department of Commerce, 588 U. S., at 768 . The causation requirement is central to Article III standing. Like the injury in fact requirement, the causation requirement screens out plaintiffs who were not injured by the defendant’s action. Without the causation requirement, courts would be “virtually continuing monitors of the wisdom and soundness” of government action. Allen, 468 U. S., at 760 (quotation marks omitted). Determining causation in cases involving suits by unregulated parties against the government is admittedly not a “mechanical exercise.” Id., at 751 . That is because the causation inquiry can be heavily fact-dependent and a “question of degree,” as private petitioner’s counsel aptly described it here. Tr. of Oral Arg. 50. Unfortunately, applying the law of standing cannot be made easy, and that is particularly true for causation. Just as causation in tort law can pose line-drawing difficulties, so too can causation in standing law when determining whether an unregulated party has standing. That said, the “absence of precise definitions” has not left courts entirely “at sea in applying the law of standing.” Allen, 468 U. S., at 751 . Like “most legal notions, the standing concepts have gained considerable definition from developing case law.” Ibid. As the Court has explained, in “many cases the standing question can be answered chiefly by comparing the allegations of the particular complaint to those made in prior standing cases.” Id., at 751–752. Stated otherwise, assessing standing “in a particular case 12 FDA v. ALLIANCE FOR HIPPOCRATIC MEDICINE Opinion of the Court may be facilitated by clarifying principles or even clear rules developed in prior cases.” Id., at 752 . Consistent with that understandi