1. Whether the government’s rescission of the Migrant Protection Protocols, 2019 violated the Immigration and Nationality Act of 1965 on mandatory detention of illegal immigrants because illegal entrants were released into the United States.
2. Whether there was anything that could prevent an agency from undertaking a new agency action while simultaneously appealing an adverse judgment against its original action.

1. Section 1252(f)(1) of the8 US Code § 1252 generally prohibited lower courts from entering injunctions that ordered federal officials to take or to refrain from taking actions to enforce, implement, or otherwise carry out the specified statutory provisions.The District Court’s injunction violated that provision. But that fact simply presented the court with the following question: whether section 1252(f)(1) deprived the court of jurisdiction to reach the merits of an appeal, where the lower court entered a form of relief barred by that provision.
2. Without section 1252(f)(1) of the 8 US Code § 1252, the District Court clearly had federal question jurisdiction over the respondents’ suit, which asserted claims arising under two federal statutes, the Immigration and Nationality Act of 1965 and the Administrative Procedure Act of 1946. The question, then, was whether section 1252(f)(1) of the 8 US Code § 1252 stripped the lower courts of subject matter jurisdiction over those claims. The parties agreed that the answer to that question was no, and so did the Supreme Court. That was because section 1252(f)(1) of the 8 US Code § 1252 withdrew a district court’s jurisdiction or authority to grant a particular form of relief. It did not deprive the lower courts of all subject matter jurisdiction over claims brought under sections 1221 through 1232 of the Immigration and Nationality Act of 1965.
3. Section 1252(f)(1) of the 8 US Code § 1252 deprived courts of the power to issue a specific category of remedies: those that enjoined or restrained the operation of the relevant sections of the statute. A limitation on subject matter jurisdiction, by contrast, restricted a court’s power to adjudicate a case. Section 1252(f)(1) of the 8 US Code § 1252 bore no indication that lower courts lacked power to hear any claim brought under sections 1221 through 1232 of the Immigration and Nationality Act of 1965.
4. If Congress had wanted the provision to have that effect, it could have said so in words far simpler than those that it wrote. But Congress instead provided that lower courts would lack jurisdiction to enjoin or restrain the operation of the relevant provisions, and it included that language in a provision whose title—Limit on injunctive relief —made clear the narrowness of its scope.
5. A second feature of the text of section 1252(f)(1) of the 8 US Code § 1252 left no doubt that that court had jurisdiction: the parenthetical explicitly preserving the court’s power to enter injunctive relief. If section 1252(f)(1) of the 8 US Code § 1252 deprived lower courts of subject matter jurisdiction to adjudicate any non-individual claims under sections 1221 through 1232, no such claims could ever arrive at the court, rendering the provision’s specific carve-out for Supreme Court injunctive relief nugatory.
6. There was no basis for the conclusion that section 1252(f)(1) of the 8 US Code § 1252 concerned subject matter jurisdiction. It was true that section 1252(f)(1) used the phrase jurisdiction or authority, rather than simply the word authority. But jurisdiction was a word of many, too many meanings. And the question whether a court had jurisdiction to grant a particular remedy was different from the question whether it had subject matter jurisdiction over a particular class of claims. Section 1252(f)(1) no doubt deprived the lower courts of jurisdiction to grant class-wide injunctive relief. But that limitation posed no obstacle to jurisdiction in the court.
7. Section 1225(b)(2)(C) plainly conferred a discretionary authority to return aliens to Mexico during the pendency of their immigration proceedings. The court had repeatedly observed that the word ‘may’ clearly connoted discretion. The use of the word may in section 1225(b)(2)(C) thus made clear that contiguous-territory return was a tool that the secretary had the authority, but not the duty, to use.
8. If Congress had intended section 1225(b)(2)(C) to operate as a mandatory cure of any noncompliance with the government’s detention obligations, it would not have conveyed that intention through an unspoken inference in conflict with the unambiguous, express term may. It would surely instead have coupled that grant of discretion with some indication of its sometimes mandatory nature—perhaps by providing that the Secretary may return certain aliens to Mexico, unless the government failed to comply with its detention obligations, in which case the Secretary had to return them. The statutory grant of discretion contained no such caveat, and the court would not rewrite it to include one.
9. By interpreting section 1225(b)(2)(C) as a mandate, the Court of Appeals imposed a significant burden upon the executive’s ability to conduct diplomatic relations with Mexico. The Migrant Protection Protocols, 2019 applied exclusively to non-Mexican nationals who had arrived at ports of entry that were located in the United States. The Executive therefore could not unilaterally return those migrants to Mexico. In attempting to rescind the Migrant Protection Protocols, 2019, the secretary emphasized that efforts to implement the Migrant Protection Protocols, 2019 had played a particularly outsized role in diplomatic engagements with Mexico, diverting attention from more productive efforts to fight transnational criminal and smuggling networks and addressed the root causes of migration.
10. Under the Court of Appeals’ interpretation, section 1225(b)(2)(C) authorized the District Court to force the executive to the bargaining table with Mexico, over a policy that both countries wished to terminate, and to supervise its continuing negotiations with Mexico to ensure that they were conducted in good faith. That stark consequence confirmed the court’s conclusion that Congress did not intend section 1225(b)(2)(C) to tie the hands of the executive in that manner.
11. The Immigration and Nationality Act of 1965 expressly authorized the Department of Homeland Security to process applicants for admission under a third option: parole. Every administration, including the Trump and the petitioner’s administrations, had utilized that authority to some extent. Importantly, the authority was not unbounded. The Department of Homeland Security could exercise its discretion to parole applicants only on a case-by-case basis for urgent humanitarian reasons or significant public benefit. And under the Administrative Procedure Act of 1946, Department of Homeland Security’s exercise of discretion within that statutory framework had to be reasonable and reasonably explained. But the availability of the parole option additionally made it clear that the Court of Appeals erred in holding that the Immigration and Nationality Act of 1965 required the government to continue implementing the Migrant Protection Protocols, 2019.
12. The contiguous-territory return authority in section 1225(b)(2)(C) was discretionary—and remained discretionary notwithstanding any violation of section 1225(b)(2)(A). The court needed not and did not resolve the parties’ arguments regarding whether section 1225(b)(2)(A) had to be read in light of traditional principles of law enforcement discretion, and whether the government was lawfully exercising its parole authorities pursuant to sections 1182(d)(5) and 1226(a). Section 1225(b)(2)(C) meant that ‘may’ meant ‘may’, and the Immigration and Nationality Act of 1965 itself did not require the Secretary to continue exercising his discretionary authority under those circumstances.
13. The Court of Appeals also erred in holding that the October 29 memoranda did not constitute a new and separately reviewable final agency action. To recap, the Secretary first attempted to terminate the Migrant Protection Protocols, 2019 through the June 1 memorandum. As the Court of Appeals correctly held, that constituted final agency action. But the District Court found that the secretary’s stated grounds in the June 1 memorandum were inadequate, and therefore vacated the June 1 Memorandum and remanded the matter to Department of Homeland Security for further consideration.
14. Both the June 1 memorandum and the October 29 memoranda, when they were issued, marked the consummation of the agency’s decision-making process and resulted in rights and obligations being determined. As the Court of Appeals explained, the June 1 Memorandum bound Department of Homeland Security staff by forbidding them to continue the program in any way from that moment on. That rationale also applied to the October 29 memoranda, which were therefore final agency action under the Administrative Procedure Act of 1946. The various rationales offered by respondents and the Court of Appeals in support of the contrary conclusion lacked merit. First, the Court of Appeals framed the question by postulating the existence of an agency decision wholly apart from any agency statement of general or particular applicability designed to implement that decision.
15. To the extent that the Court of Appeals understood itself to be reviewing an abstract decision apart from specific agency action, as defined in the Administrative Procedure Act of 1946, that was erroneous. It was not the case that the June 1 memorandum and the October 29 memoranda simply explained Department of Homeland Security’s decision, while only the decision itself had legal effect. To the contrary, the June 1 Memorandum and the October 29 memoranda were themselves the operative agency actions, each of them an agency statement designed to implement, interpret, or prescribe law or policy.
16. Second, the respondents characterized the October 29 memoranda as post hoc rationalizations of the June 1 memorandum under the court’s decision inDepartment of Homeland Security v Regents of Univ of Cal, 591 US (Regents). The prohibition on post hoc rationalization applied only when the agency proceeded by the first option from Regents. Under that circumstance, because the agency had chosen to rest on its original action while elaborating on its prior reasoning, the bar on post hoc rationalization operated to ensure that the agency’s supplemental explanation was anchored to the grounds that the agency invoked when it took the action.
17. By contrast, the secretary chose the second option from Regents, and dealt with the problem afresh by taking new agency action. That second option could be more procedurally onerous than the first—the agency had to comply with the procedural requirements for new agency action—but the benefit was that the agency was not limited to its prior reasons in justifying its decision. Indeed, the entire purpose of the October 29 memoranda was for the secretary to issue a new rescission bolstered by new reasons absent from the June 1 memorandum—reasons that he hoped would answer the District Court’s concerns from the first go-round. Having returned to the drawing table and taken new action, therefore, the secretary was not subject to the charge of post hoc rationalization.
18. In reviewing agency action, a court was ordinarily limited to evaluating the agency’s contemporaneous explanation in light of the existing administrative record. The respondents fell short of the strong showing of bad faith or improper behavior that the court required before deviating from its normal rule that the grounds upon which an administrative order had to be judged were those upon which the record disclosed that its action was based.
19. The agency’s ex ante preference for terminating the Migrant Protection Protocols, 2019 —like any other feature of an administration’s policy agenda—should not be held against the October 29 memoranda. It was hardly improper for an agency head to come into office with policy preferences and ideas and work with staff attorneys to substantiate the legal basis for a preferred policy.
20. The Court of Appeals took the agency to task for its September 29 announcement of its intention to issue in the coming weeks a new memorandum terminating the Migrant Protection Protocols, 2019. But that announcement came over six weeks after the District Court’s August 13 remand—a substantial window of time for the agency to conduct a bona fide reconsideration.
21. The Court of Appeals erred to the extent it viewed the government’s decision to appeal the District Court’s injunction as relevant to the question of the October 29 memoranda’s status as final agency action. Nothing prevented an agency from undertaking new agency action while simultaneously appealing an adverse judgment against its original action. That was particularly so under the circumstances of that case. The second condition of the District Court’s injunction, which purported to bind the Department of Homeland Security to implement the Migrant Protection Protocols, 2019 in perpetuity subject only to congressional funding choices outside its control, as a practical matter left the Government no choice but to appeal. And the agency reasonably chose to accede to the District Court’s Administrative Procedure Act of 1946 analysis of the June 1 Memorandum and sought to ameliorate those concerns in the meantime. The Government’s rescission of Migrant Protection Protocols, 2019 did not violate section 1225 of the Immigration and Nationality Act of 1965, and the October 29 memoranda did constitute final agency action.

Per Alito, Thomas & Gorsuch, SCJJ (dissenting)

1. Due to the huge numbers of aliens who attempted to enter illegally from Mexico, the Department of Homeland Security did not have the capacity to detain all inadmissible aliens encountered at the border, and no one suggested that the Department of Homeland Security had to do the impossible. But rather than avail itself of Congress’s clear statutory alternative to return inadmissible aliens to Mexico while they await proceedings in America, the Department of Homeland Security had concluded that it could forgo that option altogether and instead simply release into America untold numbers of aliens who were very likely to be removed if they showed up for their removal hearings. That practice violated the clear terms of the law, but the court looked the other way.
2. In doing so, the majority committed three main errors. First, it unnecessarily resolved difficult jurisdictional questions on which—due to the government’s litigation tactics—the court had received only hurried briefing and no argument. Second, when the majority reached the merits, it contrived a way to overlook the clear statutory violations that resulted from the Department of Homeland Security’s decision to terminate the use of its contiguous-territory return authority. Finally, the majority unjustifiably faulted the Court of Appeals for rejecting the government’s last-minute attempt to derail the ordinary appellate process.
3. The October 29 memoranda did not moot the appeal. A case became moot only if it was impossible for the court to grant any effectual relief. Under that high standard, the Fifth Circuit was correct that the case was not moot. Although the government claimed that the appeal was moot, it asked the Court of Appeals for relief, namely, vacatur of District Court’s injunction. It was compelled to take that position because the October 29 memoranda, by their own terms, did not take effect as long as that injunction remained in force. And without an appellate decision holding that the Immigration and Nationality Act of 1965 allowed the government to release aliens who could be returned to Mexico, the issuance of a new administrative order terminating the Migrant Protection Protocols, 2019 could not provide a ground for vacating the injunction. It was telling that the government’s briefing in that the court never suggested that the case was moot at the time of the Fifth Circuit’s decision or that the case was then moot.
4. The Court of Appeals did not err by declining to hold the appeal in abeyance. The government originally asked the Court of Appeals to hold the appeal while it completed the process of issuing a new termination decision, but by the time of oral argument in that court, the government claimed that such a decision had been issued. And the government did not file a motion in the District Court to vacate its judgment under Federal Rule of Civil Procedure 60(b). The government had sought to expedite proceedings at every stage, including by seeking emergency relief in the Fifth Circuit and the court, and under those circumstances, it was eminently reasonable for the Court of Appeals to conclude that additional delay would not have served the interests of economy of time and effort.
5. The Court of Appeals correctly concluded that the October 29 memoranda could not satisfy our criteria for a final agency action that could be reviewed in the first instance in the Court of Appeals under the Administrative Procedure Act of 1946. Like the Supreme Court, the courts of appeal were courts of review, and not first view. With no administrative record for the October 29 memoranda before it, the Court of Appeals was in a poor position to assess whether the memoranda actually marked the consummation of the agency’s decision-making process.
6. Moreover, the October 29 memoranda did not purport to result in a final determination of rights or obligations. As the Department of Homeland Security acknowledged, the termination of the Migrant Protection Protocols, 2019 could not be implemented until there was a final judicial decision to vacate the injunction. And until that was accomplished, the memoranda did not impose on the Department of Homeland Security officers or employees any obligation to cease implementation of the Migrant Protection Protocols, 2019. The Fifth Circuit rightly understood that the October 29 memoranda could have no legal effect while the Department of Homeland Security was bound by an injunction to implement the Migrant Protection Protocols, 2019 in good faith and that that injunction would remain in force unless the government’s challenge to the June termination wasdecided in its favor.
7. Even if the Fifth Circuit had somehow concluded that the October 29 memoranda constituted final agency action with some future legal consequences, the court did not explain what the Fifth Circuit should have done differently in the circumstances it faced. The Fifth Circuit had little ability to review whether the agency had acted reasonably.

Per Barrett, Thomas, Alito & Gorsuch (dissenting)

1. The lower courts in that case had concluded that 8 USC §1252(f)(1), a provision of the Immigration and Nationality Act sharply limiting federal courts’ jurisdiction or authority to enjoin or restrain the operation of certain immigration laws, did not present a jurisdictional bar. The Supreme Court had repudiated their reasoning in Garland v Aleman Gonzalez, 596 US (2022) (Aleman Gonzalez). Because the Supreme Court was a court of review and not first view, it was better to vacate and remand for the lower courts to reconsider their assertion of jurisdiction in light of Aleman Gonzalez.
2. The Court assumed that it was facing an either/or choice between subject-matter jurisdiction and remedial authority, with the former being only about a court’s authority to decide merits questions and the latter being only about the relief a court can grant. That dichotomy made the Court’s job easier, because it could use the obvious point that §1252(f)(1) stripped lower courts of remedial authority to establish that §1252(f)(1) did not strip them of subject-matter jurisdiction. However, Congress was free to link a court’s subject-matter jurisdiction to its remedial authority.