607 U.S. ___ (2025)

Only the Westlaw citation is currently available.
2025 WL 3715211

Supreme Court of the United States.
Donald J. TRUMP, President of the United States, et al.
v.
ILLINOIS, et al.
No. 25A443
|
December 23, 2025

Opinion
[Joined by CJ Roberts, Barrett, Jackson Kagan, Kavanaugh, and Sotomayor)

Federal immigration-enforcement efforts have encountered significant resistance, as well as some violence, in Chicago. According to the Government, federal officers have been obstructed, threatened, and assaulted as they attempt to perform their duties. The Government also alleges that an Immigration and Customs Enforcement processing facility in Broadview, Illinois, has been the site of frequent and sometimes violent protests, damaging federal property and threatening the safety of federal officers. These attacks, the Government says, have greatly impeded its efforts to enforce the immigration laws.
 
On October 4, 2025, the President called 300 members of the Illinois National Guard into active federal service to protect federal personnel and property in Illinois, particularly in and around Chicago. The following day, members of the Texas National Guard were also federalized and sent to Chicago. In calling forth the Guard, the President relied on 10 U.S.C. § 12406(3), which empowers him to federalize members of the Guard if he is “unable with the regular forces to execute the laws of the United States.”
 
The United States District Court for the Northern District of Illinois entered a temporary restraining order bar ring the federalization and deployment of the Guard in Illinois. The Seventh Circuit denied in relevant part the Government’s motion for a stay, permitting the Guard to remain federalized within Illinois but maintaining the bar on deployment.
 
The Government asked this Court to stay the District Court’s order. After the response and reply were filed, Justice BARRETT referred the application to the Court. We directed the parties to file supplemental letter briefs on an issue that the District Court had addressed but the parties’ initial briefs had not: the meaning of the term “regular forces” in § 12406(3). In its supplemental brief, the Government argues that the term refers to civilian law enforcement officers, such as those employed by Immigration and Customs Enforcement or the Federal Protective Service. Respondents, echoing the District Court, maintain that the term refers to the regular forces of the United States military.
 
[1]We conclude that the term “regular forces” in § 12406(3) likely refers to the regular forces of the United States military. This interpretation means that to call the Guard into active federal service under § 12406(3), the President must be “unable” with the regular military “to execute the laws of the United States.” Because the statute requires an assessment of the military’s ability to execute the laws, it likely applies only where the military could legally execute the laws. Such circumstances are exceptional: Under the Posse Comitatus Act, the military is prohibited from “execut[ing] the laws” “except in cases and under circumstances expressly authorized by the Constitution or Act of Congress.” 18 U.S.C. § 1385. So before the President can federalize the Guard under § 12406(3), he likely must have statutory or constitutional authority to execute the laws with the regular military and must be “unable” with those forces to perform that function.
 
[2]At this preliminary stage, the Government has failed to identify a source of authority that would allow the military to execute the laws in Illinois. The President has not invoked a statute that provides an exception to the Posse Comitatus Act. Instead, he relies on inherent constitutional authority that, according to the Government, allows him to use the military to protect federal personnel and property. But the Government also claims—consistent with the longstanding view of the Executive Branch—that performing such protective functions does not constitute “execut[ing] the laws” within the meaning of the Posse Comitatus Act. See Supp. Letter Reply Brief for Applicants 8; 1 Supp. Op. OLC 343, n. 1 (1971) (collecting sources). If that is correct, it is hard to see how performing those functions could constitute “execut[ing] the laws” under § 12406(3). See Azar v. Allina Health Services, 587 U.S. 566, 574, 139 S.Ct. 1804, 204 L.Ed.2d 139 (2019) (“This Court does not lightly assume that Congress silently attaches different meanings to the same term in the same or related statutes”). Thus, at least in this posture, the Government has not carried its burden to show that § 12406(3) permits the President to federalize the Guard in the exercise of inherent authority to protect federal personnel and property in Illinois. We need not and do not address the reviewability of findings made by the President under § 12406(3) or any other statute.
 
The application for stay is denied. 

Justice KAVANAUGH, concurring in the judgment.

To protect federal personnel and property in Illinois, the President federalized about 300 National Guard members. The State of Illinois sued, and as relevant here, the District Court barred the President from deploying the Guard. After the Seventh Circuit declined to stay the District Court’s order, the Government applied to this Court for a stay. I agree with the Court’s decision to deny the Government’s application for a stay, but I would do so on narrower grounds.
 
To federalize the National Guard, the President first must determine that he is “unable with the regular forces to execute the laws of the United States.” 10 U.S.C. § 12406(3). In my view, the statutory term “regular forces” likely refers to the U. S. military, not to federal civilian law enforcement officers. On the current record, however, it does not appear that the President has yet made the statutorily required determination that he is “unable” with the U. S. military, as distinct from federal civilian law enforcement officers, to ensure the execution of federal law in Illinois. (The President of course would have great discretion to make that determination, as the State itself acknowledges. See Supp. Letter Reply Brief for Respondents 7; Department of Navy v. Egan, 484 U.S. 518, 529–530, 108 S.Ct. 818, 98 L.Ed.2d 918 (1988).)
 
On that narrow ground, I would deny the Government’s application for a stay. We need not decide more, so I would not decide more.
 
The Court goes further. The Court starts by concluding that “regular forces” means the U. S. military. (As noted above, I agree with that initial point.) From there, however, the Court conducts a complicated and debatable statutory analysis. The Court says that under the Government’s argument, “it is hard to see how performing those functions”—that is, protecting federal personnel and property—“could constitute ‘execut[ing] the laws’ under § 12406(3).” Ante, at ––––. On that premise, the Court further states that “at least in this posture, the Government has not carried its burden to show that § 12406(3) permits the President to federalize the Guard in the exercise of inherent authority to protect federal personnel and property in Illinois,” ante, at ––––—even if the President finds that he is “unable” with the U. S. military to protect federal personnel and property from harm.1
 
The Court’s legal interpretation, as I understand it, could lead to potentially significant implications for future crises that we cannot now foresee. Consider a hypothetical example. Suppose a mob rapidly gathers outside the U. S. Courthouse in Philadelphia in response to an unpopular decision (or to influence the outcome of a pending matter). Suppose also that the mob is threatening to storm the courthouse and attack the federal judges, prosecutors, and other personnel inside, and to damage or burn down the building, thereby preventing the execution of federal law. Suppose further that U. S. military forces cannot readily mobilize to deploy to the site in time, that the local police and federal court security officers are outnumbered, and that the President wants to federalize National Guard units to protect the courthouse and the judges, prosecutors, and other personnel. Under the Court’s order today, even in those circumstances the President presumably could not federalize the National Guard under § 12406(3).2
 
Of course, that kind of hypothetical scenario does not often arise, and we can hope that it will not arise in the future. But the potential consequences, combined with the novelty and difficulty of the statutory issues addressed by the Court, underscore why I would not opine more broadly than necessary to resolve this application.3
 
Before addressing those challenging and far-reaching statutory questions at this stage of the case, I would have at least invited further briefing and possibly also held oral argument, either on the application itself or by granting certiorari before judgment, akin to what the Court has done on several recent occasions. See Trump v. CASA, Inc., 606 U.S. 831, 145 S.Ct. 2540, 222 L.Ed.2d 930 (2025); Ohio v. EPA, 603 U.S. 279, 144 S.Ct. 2040, 219 L.Ed.2d 772 (2024); National Federation of Independent Business v. OSHA, 595 U.S. 109, 142 S.Ct. 661, 211 L.Ed.2d 448 (2022). As I have stated with respect to previous interim applications of substantial import and difficulty, the Court can help guard against mistakes or misjudgments by employing additional process when sufficient time is available—recognizing, of course, that time will not always be available. See Trump v. Boyle, 606 U. S. ––––, 145 S.Ct. 2653, 222 L.Ed.2d 1181 (2025) (KAVANAUGH, J., concurring); Trump v. CASA, Inc., 606 U.S. at 876, 145 S.Ct. 2540 (KAVANAUGH, J., concurring); A.A.R.P. v. Trump, 605 U.S. 91, 100, 145 S.Ct. 1364, 221 L.Ed.2d 765 (2025) (KAVANAUGH, J., concurring); Labrador v. Poe, 601 U. S. 1110, 1127–1129, 144 S.Ct. 921, 218 L.Ed.2d 400 (2024) (KAVANAUGH, J., concurring).4
 
In sum, I vote to deny the application but would do so on narrow grounds and, at this time, would not reach the broader statutory issues addressed by the Court.

Justice ALITO, with whom Justice THOMAS joins, dissenting.

*1 “ ‘In our adversarial system of adjudication, we follow the principle of party presentation.’ ” Clark v. Sweeney, 607 U. S. ––––, ––––, ––– S.Ct. ––––, ––– L.Ed.2d ––––, 2025 WL 3260170 (2025) (per curiam) (slip op., at 2) (quoting United States v. Sineneng-Smith, 590 U.S. 371, 375, 140 S.Ct. 1575, 206 L.Ed.2d 866 (2020)). If a party passes up what seems to us a promising argument, we do not assume the role of advocate. Instead, we normally decide the questions that the parties choose to present.
 
In this case, the Court has unnecessarily and unwisely departed from standard practice. It raised an argument that respondents waived below, and it now rules in respondents’ favor on that ground. …

I
A
The key statutory provision in this case, 10 U.S.C. § 12406(3), provides in relevant part that “[w]henever ... the President is unable with the regular forces to execute the laws of the United States,” he “may call into Federal service members and units of the National Guard of any State in such numbers as he considers necessary to ... execute those laws.”
 
*2 In the lower courts, the parties agreed that the phrase “regular forces” means civilian federal law enforcement officers, not military service members. Respondents explicitly adopted this position in the District Court. That court disagreed, but when the Government challenged this holding in the Seventh Circuit, respondents declined to defend the lower court’s interpretation, and the Seventh Circuit did not reach the issue. The Government’s stay application in this Court asserted that any defense of the District Court’s interpretation had been waived, and respondents did not dispute either that assertion or the correctness of the Government’s contention that “regular forces” means federal civilian officers. Thus, the argument that “regular forces” means the military was either waived or forfeited three times over.
 
Ignoring this history, the Court ordered the parties to file supplemental briefs on the meaning of “regular forces.” Respondents “[u]nderstandably ... rode with an argument suggested by” the Court and argued, for the first time and contrary to their position below, that the “regular forces” means the military. Sineneng-Smith, 590 U.S. at 379, 140 S.Ct. 1575. The majority now accepts this eleventh-hour argument. “Nevermind that [respondents] had presented a contrary theory of the case in the District Court.” Id., at 380, 140 S.Ct. 1575. For the Court, respondents’ “own arguments, differently directed, fell by the wayside, for they did not mesh with” the Court’s own “theory of the case.” Id., at 379, 140 S.Ct. 1575.
 
We should decide this application based on the “party-presented controversy.” Id., at 380, 140 S.Ct. 1575. That controversy centered on the District Court’s holding that, contrary to the President’s determination, civilian federal law enforcement officers were in fact able to execute federal laws in the Chicago area. If the Court has doubts about the parties’ interpretation of the phrase “regular forces,” it could assume for the sake of argument that the parties’ interpretation was correct and proceed on that basis. The Court has done that on many occasions. E.g., Warner Chappell Music, Inc. v. Nealy, 601 U.S. 366, 371, 144 S.Ct. 1135, 218 L.Ed.2d 363 (2024) (assuming there is a discovery rule for copyright claims); Financial Oversight and Management Bd. for P. R. v. Centro de Periodismo Investigativo, Inc., 598 U.S. 339, 345, 346, 143 S.Ct. 1176, 215 L.Ed.2d 321 (2023) (“assum[ing] without deciding that Puerto Rico is immune from suit in federal district court and that [a financial oversight board] partakes of that immunity” because respondent “never argued” otherwise in the courts below); Wisconsin Legislature v. Wisconsin Elections Comm’n, 595 U.S. 398, 401, 142 S.Ct. 1245, 212 L.Ed.2d 251 (2022) (per curiam) (assuming without deciding that complying with the Voting Rights Act is a compelling interest); McDonough v. Smith, 588 U.S. 109, 115, 139 S.Ct. 2149, 204 L.Ed.2d 506 (2019) (assuming without deciding that a due process fabricated-evidence claim may be asserted under Rev. Stat. § 1979, 42 U.S.C. § 1983).
 
In this case, the Court has no good reason to stray beyond the issues that the parties chose to present, and based on those arguments, the Court should grant the application. There is no basis for rejecting the President’s determination that he was unable to execute the federal immigration laws using the civilian law enforcement resources at his command. In concluding otherwise, the District Court likely committed both legal and factual error.
 
…

Justice GORSUCH, dissenting.

This case touches on sensitive and gravely consequential questions concerning what roles the National Guard and U. S. military may play in domestic law enforcement. To be sure, as the parties observe, Congress has supplied us with some relevant statutory guidance in 10 U.S.C. § 12406(3). But, as my colleagues’ writings attest, that statute raises as many questions as it answers.
 
Take just some examples. Before calling up the National Guard under § 12406(3), must the President be unable to execute the laws merely with federal civilian law enforcement personnel—or must he be unable to do so even with military troops? Is a Presidential declaration that he is unable with the regular forces to execute the law judicially reviewable—and, if so, to what extent and under what standard? Does § 12406(3) provide standalone authority permitting the President to deploy the Guard, and how does it interact with other statutes in the field, such as the Posse Comitatus Act, 18 U.S.C. § 1385, and the Insurrection Act, 10 U.S.C. §§ 251–255? What, if any, inherent Article II power does the President have to deploy the Guard to protect federal personnel or property, and how might that inform the interpretation of § 12406(3)? And if, as all parties seem to assume, today’s Guard is the successor to the militia of the founding era, how far can this inherent Presidential authority extend before it intrudes on Congress’s prerogative to decide when the militia may be used to execute the laws? See Art. I, § 8, cl. 15. If all those questions were not fraught enough, an even graver one lurks here too: When, if ever, may the federal government deploy the professional military for domestic law enforcement purposes consistent with the Constitution? See, e.g., Art. IV, § 4; Amdt. 14, § 5.
 
In the present posture of this case, I am not comfortable venturing an answer to any of those questions. This Court has never decided a case about the meaning of § 12406(3), let alone explored its interaction with other statutes in the field or the Constitution. Nor do we have much help on many of these matters from the parties’ briefs before us, understandably given that this case comes to us in an interlocutory posture on a highly compressed schedule.
 
Under these circumstances, caution seems to me key, and I would decide this application narrowly, based only on those few arguments the parties preserved and the evidentiary record as it stands. See United States v. Sineneng-Smith, 590 U.S. 371, 375, 140 S.Ct. 1575, 206 L.Ed.2d 866 (2020). In their initial briefing before this Court, the parties proceeded on the premise that § 12406(3) statutorily permits the President to call up and deploy the National Guard when he is unable to execute federal law with civilian federal law enforcement officials. Proceeding on that same premise, I believe the declarations federal law enforcement officials submitted below support the grant of a stay for substantially the reasons given in Parts I–A, B–1, C, and D of Justice ALITO’s opinion. See ante,at –––– – ––––. But I would hazard no opinion beyond that, leaving instead all the weighty questions outlined above for another case where they are properly preserved and can receive the full airing they so clearly deserve.

Footnotes [omitted]