WHEN CAN A PRESIDENT DEPLOY THE NATIONAL GUARD OVER A GOVERNOR’S OBJECTION?

Feb 16

Author: Jack Trusty, Senior Editor

Introduction

A debate has broken out over who controls the use of National Guard troops on U.S. soil.[i] The dispute began in Chicago, where federal officials claimed that immigration enforcement efforts were being blocked by local protests.[ii] Government reports claimed that federal officers were harassed, threatened, and physically obstructed.[iii] On October 4th, 2025, President Trump responded by calling 300 members of the Illinois National Guard into federal service; Guard units from Texas were also activated and sent to Chicago.[iv]

Illinois filed suit on October 6th.[v] After the district court’s interim order, the government sought a stay in the Seventh Circuit, which allowed the Guard to remain federalized but kept the deployment barred.[vi] This prompted the government’s emergency stay application to the Supreme Court.[vii] A stay application is a request to pause a lower court’s order temporarily while the case continues, not a request for the Supreme Court to resolve the entire dispute on the merits.[viii] That is why the Court described this as a “preliminary stage”: the record is not fully developed, and the Court is deciding whether the government has shown enough to justify temporary relief pending further proceedings below.[ix] Trump v. Illinois showed that the answers will depend on how courts interpret statutory text—and how closely the Executive’s claims match what the law allows. [x]

Background

Immigration enforcement is a federal responsibility.[xi] The federal government has primary authority over the admission, removal, and regulation of noncitizens.[xii] In Trump v. Illinois, the federal government alleged that conditions in Chicago had deteriorated during immigration operations.[xiii] Their claim was that federal officers operated under sustained threat, while federal property was also damaged.[xiv] These claims formed the factual basis for the President’s response.[xv] The President did not declare an insurrection; instead, the government framed the deployment as a response to operational failure under 10 U.S.C. § 12406(3).[xvi]

Section 12406 and the Court Majorities Interpretation

§ 12406 Overview

Section 12406 governs when National Guard units may be brought into federal service.[xvii] It reflects Congress’s effort to keep the Guard primarily under state control, while allowing it to be placed into federal service in limited circumstances.[xviii] “The statute lists three triggers: (1) the United States (or any Commonwealth)‘is invaded or is in danger of invasion by a foreign nation’; (2) ‘there is a rebellion or danger of a rebellion against the authority of the Government of the United States’; or (3) the President ‘is unable with the regular forces to execute the laws of the United States.’[xix] Section 12406 (3) was the sole basis for the Chicago deployment.[xx]

“Regular forces”

The government argued that “regular forces” included civilian federal personnel, such as ICE officers.[xxi] They theorize that if civilian agencies face operational difficulties, it would be justifiable to federalize the Guard.[xxii] The Court rejected the government’s interpretation.[xxiii] Instead, it read “regular forces” to mean the United States’ regular armed forces.[xxiv] The Court continued by explaining that if “regular forces” refers to the military, then § 12406(3) is triggered only when the President is unable, using the military, to execute federal law.[xxv] This military-focused definition fits the kind of statute this is. Section 12406 sits in Title 10, the part of the U.S. Code that governs military forces.[xxvi] It is a call-up provision: it explains when the President may take National Guard units that ordinarily operate under state control and place them into federal service.[xxvii] Therefore, the statute’s reference to “regular forces” points to the standing U.S. armed forces, not to civilian agencies like ICE.[xxviii] The Court treated this military interpretation as the better reading at the preliminary stage and proceeded on that basis.[xxix] By reading “regular forces” to mean the regular military, the Court made legality under Posse Comitatus part of the § 12406(3) inquiry.[xxx]

“Execute the laws” and the Posse Comitatus

Once the Court adopted that definition of what “regular forces” likely means, another issue followed.[xxxi] The military generally may not execute domestic law.[xxxii] The Posse Comitatus Act prohibits using the Army, Navy, Marine Corps, Air Force, or Space Force “to execute the laws” unless the action is “expressly authorized by the Constitution or Act of Congress.”[xxxiii] The Court’s point was that, once “regular forces” means the regular military, the government must identify a lawful source of authority that would allow the regular military to execute domestic law in the first place, and then show why the President is “unable” to use that authority.[xxxiv]

The government failed to point to any statute that would allow the military to execute the laws in Illinois.[xxxv] Instead, it relied on inherent Article II authority to protect federal personnel and property.[xxxvi] It also argued that this kind of protective action does not qualify as “executing the laws” under the Posse Comitatus Act.[xxxvii] The phrase “execute the laws” appears in both § 12406(3) and Posse Comitatus; the majority were not willing to assume that Congress intended different meanings in each context without making that distinction explicit.[xxxviii] Because the government had not shown lawful authority for the regular military to “execute the laws” in Illinois, the Court concluded that the government had not carried its burden to justify a Guard call-up under § 12406(3) on this record.[xxxix]

Implications for the Future

Deployment in Illinois remains blocked under existing orders.[xl] The Court’s order signals that § 12406(3) is not a general emergency power.[xli] “Regular forces” likely means the military, and inability must be assessed against lawful military authority.[xlii] Therefore, the president must identify lawful authority for military enforcement and show inability with those forces.[xliii] Because the Court denied relief at a preliminary stage and emphasized what the government had not shown “on this record,” future cases may turn on whether the government can identify a specific constitutional or statutory source that authorizes domestic “law execution” by the regular military in the circumstances presented.[xliv] Only then will the fight shift to what evidence is enough to establish that the President is “unable with the regular forces” under § 12406(3), once a lawful baseline authority is identified.[xlv]

Conclusion

Trump v. Illinois is a stay-stage statutory decision, but it clarifies the direction of future litigation. The Court read “regular forces” in § 12406(3) to mean the regular armed forces, not federal civilian law enforcement.[xlvi] A President invoking § 12406(3) must be able to point to some constitutional or statutory basis that would allow the regular military to “execute the laws” in the relevant setting, because § 12406(3) asks whether the President is “unable with regular forces” to do that job.[xlvii] On the record presented, the government did not identify such authority, and the Court therefore denied the stay.[xlviii] The opinion instead forces future cases to match the Executive’s asserted mission to the statutory words Congress chose, especially the phrase “execute the laws”, and to confront how that phrase operates across § 12406(3) and the Posse Comitatus Act.

[i] Amy Howe, Supreme Court Rejects Trump’s Effort to Deploy National Guard in Illinois, SCOTUSBLOG (Dec. 23, 2025), https://www.scotusblog.com/2025/12/supreme-court-rejects-trumps-effort-to-deploy-national-guard-in-illinois.

[ii] Id.

[iii] Id.

[iv] Complaint at 1, State of Illinois v. Trump, No. 1:25-cv-12174, 2025 U.S. Dist. LEXIS 201113, (N.D. Ill. filed Oct. 6, 2025).

[v] Id.

[vi] Illinois v. Trump, 155 F.4th 929, 940 (7th Cir. 2025).

[vii] Trump v. Illinois, No. 25A443, at 1 (U.S. Dec. 23, 2025).

[viii] Stay, Black’s Law Dictionary (12th ed. 2024).

[ix] Trump, No. 25A443, 2.

[x] Id. at 1-3.

[xi] Arizona v. United States, 567 U.S. 387, 394-95 (2012).

[xii] Id.

[xiii] Trump, No. 25A443, at 1.

[xiv] Id.

[xv] Id.

[xvi] Id.

[xvii] 10 U.S.C. § 12406 (2022).

[xviii] Dan Maurer, The Governor’s Role in Federalizing the National Guard Under 10 U.S.C. § 12406, Lawfare (Oct. 2020), https://www.lawfaremedia.org/article/the-governor-s-role-in-federalizing-the-national-guard-under-10-u.s.c.-12406.

[xix] 10 U.S.C. § 12406.

[xx] Trump, No. 25A443, 1-3.

[xxi] Id. at 2.

[xxii] Id. at 1.

[xxiii] Id. at 2.

[xxiv] Id.

[xxv] Trump, No. 25A443, 2-3.

[xxvi] 10 U.S.C. § 12406.

[xxvii] Trump, No. 25A443, 2.

[xxviii] Id.

[xxix] Id.

[xxx] Id.