Trump v. Illinois: Presidential Power to Federalize the National Guard During Domestic Unrest
In October 2025, a major constitutional clash erupted when President Donald Trump invoked executive power to federalize parts of the Illinois National Guard to assist with Immigration and Customs Enforcement operations. The administration justified the move by citing what it described as escalating threats against federal officers and attacks on federal property. In response, Illinois Governor J.B. Pritzker and the City of Chicago filed suit, challenging the deployment as an overreach of executive authority.
Under 10 U.S.C. § 12406, the President may call a state’s Guard into federal service only under narrow conditions: invasion (or danger of invasion), rebellion, or when civil authorities are unable to enforce federal law. Illinois argues that none of these conditions apply: that Chicago is under no sort of invasion threat, that protest activity, though tense, has not disabled state institutions, and that federal agents in Chicago continue operating. By treating politically charged protests near ICE facilities as a “rebellion,” Illinois warns, the executive is trying to convert a limited emergency power into a routine tool of federal intervention.
On October 9, U.S. District Judge April Perry issued a temporary restraining order (TRO) blocking deployment of the Guard into Illinois. In her ruling, she expressed doubt about the administration’s version of events, writing that while there have been “acts of vandalism, civil disobedience, and even assaults on federal agents,” the evidence did not support the kind of “danger of rebellion” required under § 12406. Perry further criticized the federal government for not demonstrating that it first tried to use its “regular forces” before federalizing the Guard—a key statutory requirement.
The administration promptly appealed. On October 16th, at the Seventh Circuit, a three-judge panel narrowed Judge Perry’s order. While they allowed the Guard to remain under federal control, they upheld her prohibition on deploying troops into Illinois. The panel emphasized that, even under substantial deference to the president, courts retain a role in assessing whether the circumstances justify deployment and found the factual record lacking. As they put it, “political opposition is not rebellion.”
Shortly thereafter, the Trump administration filed an emergency application with the Supreme Court, requesting that the justices stay the lower-court orders and permit the deployment to proceed. In its petition, the government warned that the TRO undermines the President’s authority as Commander-in-Chief and jeopardizes the safety of federal personnel. Meanwhile, Illinois and Chicago countered with a response brief claiming that the deployment would escalate tensions, erode local law-enforcement authority, and risk turning military force into a regular part of domestic immigration enforcement.
On October 29, the Supreme Court asked both sides to file supplemental briefing on a key statutory clarification: what exactly “regular forces” means in § 12406, and whether that term refers to professional military or can include civilian law-enforcement agencies. According to the government, “regular forces” refers to law-enforcement agencies like the Department of Homeland Security (DHS) and Immigration and Customs Enforcement (ICE), whereas Illinois argues that the phrase must mean the U.S. military.
On December 23rd, the Supreme Court denied the Government’s emergency application for a stay, leaving in place lower court orders barring the President from deploying the National Guard to assist ICE in Illinois pending resolution on the merits. The Court concluded that the Government had failed to demonstrate a likelihood of success, emphasizing that the President had not made the requisite finding that “regular forces” were unable to execute the law, a point Justice Kavanaugh described as dispositive on the stay application. At the same time, however, the unsigned opinion advanced only “tentative” conclusions regarding the meaning of 10 U.S.C. § 12406 and its interaction with the Posse Comitatus Act, while multiple dissents warned against resolving “far-reaching” statutory and constitutional questions on an emergency posture. The immediate consequence is straightforward: the injunction remains in effect, and the deployment cannot proceed. However, the fractured and provisional reasoning leaves the scope of presidential authority unsettled, an outcome that offers little guidance to lower courts or political actors at a time of national uncertainty.