Illinois and the City of Chicago sued the Trump administration in October 2025 to stop the federalization and deployment of National Guard troops in the Chicago area, and they won. A federal judge blocked the deployment within days, the Seventh Circuit largely upheld that block, and on December 23, 2025, the Supreme Court denied the administration’s emergency stay application by a 6–3 vote. The Trump Chicago National Guard lawsuit ended on April 20, 2026, when U.S. District Judge April Perry dismissed it as moot after all federalized troops had been withdrawn.
Why Illinois and Chicago Sued
On October 4, 2025, Secretary of Defense Peter Hegseth invoked 10 U.S.C. § 12406 to federalize up to 300 members of the Illinois National Guard over the objection of Governor JB Pritzker. The next day, the administration ordered up to 400 Texas National Guard members to deploy to Illinois as well, under an operation the administration called “Operation Midway Blitz.”1White House. Department of War Security for the Protection of Federal Personnel and Property in Illinois The stated purpose was to protect federal personnel and property, in particular an Immigration and Customs Enforcement facility in Broadview that had been the site of weeks of protests.2Illinois Attorney General. Illinois v. Trump Complaint
Pritzker called the move “absolutely outrageous and un-American” and said the Pentagon had delivered an ultimatum: “Call up your troops, or we will.”3Politico. Trump National Guard Illinois Mayor Brandon Johnson called the deployment “illegal and dangerous” and signed an executive order on October 6 prohibiting federal agents from using city property for enforcement actions.4WTTW News. Johnson Vows to Resist Trump’s National Guard Deployment That same day, Illinois Attorney General Kwame Raoul and the City of Chicago filed the lawsuit in the Northern District of Illinois, Case No. 25-cv-12174, seeking a temporary restraining order and permanent injunction.5Illinois Attorney General. Attorney General Raoul Files Lawsuit Against Trump Administration
What the Lawsuit Argued
The complaint attacked the deployment on four fronts. It argued that the administration failed to meet the prerequisites of 10 U.S.C. § 12406, which allows involuntary federalization of the Guard only in cases of invasion, rebellion, or inability to execute federal law with regular forces, and which requires the order to be issued “through the governor.” It argued the deployment would violate the Posse Comitatus Act’s prohibition on using the military for civilian law enforcement. It argued that federalizing the Guard without the governor’s consent commandeered state resources in violation of the Tenth Amendment and infringed on Illinois’s police powers. And it argued the orders were unlawful agency action under the Administrative Procedure Act.
Raoul put the stakes this way: “The American people, regardless of where they reside, should not live under the threat of occupation by the United States military, particularly not simply because their city or state leadership has fallen out of a president’s favor.”6NPR. Illinois and Chicago Sue the Trump Administration Over National Guard Deployment
The District Court and Seventh Circuit Rulings
At an October 9 hearing, U.S. District Judge April Perry issued a temporary restraining order barring the deployment of National Guard troops within Illinois. She found “no credible evidence that there is danger of rebellion in the state of Illinois,” said Department of Homeland Security assessments of the Broadview protests were “unreliable,” and observed that the presence of National Guard troops was itself “likely to lead to civil unrest.”7CNN. National Guard Deployments On October 22, Perry extended the TRO indefinitely.8PBS NewsHour. Judge Blocks National Guard From Chicago Indefinitely
The administration appealed. On October 16, a Seventh Circuit panel of Judges Rovner, Hamilton, and St. Eve largely upheld Judge Perry. The court wrote that “political opposition is not rebellion” and that a protest does not become a rebellion “merely because of sporadic and isolated incidents of unlawful activity or even violence committed by rogue participants.” It also described sending another state’s National Guard into Illinois as an “incursion on Illinois’s sovereignty.”9U.S. Court of Appeals for the Seventh Circuit. State of Illinois v. Trump, No. 25-2798 The panel let the formal federalization stand but kept the bar on actual deployment within Illinois.10First Amendment Encyclopedia. Illinois v. Trump, 7th Circuit
The Supreme Court’s Decision
The administration filed an emergency application at the Supreme Court, No. 25A443, seeking a stay so troops could deploy. On October 29, the Court took the unusual step of asking for supplemental briefing on a question the justices framed themselves: whether “regular forces” in 10 U.S.C. § 12406 refers to the U.S. military or to civilian law-enforcement officers.11SCOTUSblog. Supreme Court Requests Further Information in National Guard Case
That question controlled the case. The statute allows the president to federalize the Guard when he is “unable with the regular forces to execute the laws.” Solicitor General D. John Sauer argued “regular forces” meant civilian officers such as ICE and the Federal Protective Service, which would let the administration argue it had exhausted those options. Illinois and Chicago argued the term meant the full-time professional military, in which case the Posse Comitatus Act’s bar on domestic military law enforcement left the administration unable to show it had met the statute’s threshold.12SCOTUSblog. A Delayed National Guard Deployment and Other Issues on the Interim Docket
On December 23, 2025, the Court denied the stay 6–3.13U.S. Supreme Court. Trump v. Illinois, No. 25A443 The unsigned majority opinion, joined by Chief Justice Roberts and Justices Sotomayor, Kagan, Barrett, and Jackson, held that “regular forces” means the U.S. military. Because the Posse Comitatus Act generally bars the military from executing domestic laws, and because the president had not invoked any statutory exception to it, the administration could not show it was “unable” with the regular military to execute federal law.14Brennan Center for Justice. Trump v. Illinois: Narrow Supreme Court Decision, Broad Implications The Court also pointed out an internal contradiction in the administration’s position: if protecting federal property is not “executing the laws” under the Posse Comitatus Act, those same protective functions cannot be “executing the laws” for the purpose of triggering § 12406.
Justice Kavanaugh concurred in the result on narrower grounds, agreeing that “regular forces” means the military but faulting the majority for reaching broader questions without oral argument. He warned the ruling “could cause the president to use the US military more than the National Guard” for domestic protective missions.15CNN. National Guard Trump Insurrection Act Supreme Court Justice Alito, joined by Justice Thomas, dissented, arguing the president’s determination deserved judicial deference. Justice Gorsuch dissented separately, saying the Court should have granted the stay and deferred the statutory questions for a case with full briefing.16SCOTUSblog. Supreme Court Rejects Trump’s Effort to Deploy National Guard in Illinois
How the Case Ended
On December 31, 2025, President Trump announced on Truth Social that he was pulling back federalized Guard forces from Chicago, Los Angeles, and Portland, adding: “We will come back, perhaps in a much different and stronger form, when crime begins to soar again – Only a question of time!”17CNN. Trump National Guard Withdrawal Chicago Los Angeles Portland Hegseth issued an oral order that same day ending the Illinois deployment’s extension.18WBEZ. Trump Chicago National Guard Midway Blitz Only a small number of troops had briefly been active at the Broadview facility before Judge Perry’s October 9 TRO; the rest had been held at training sites near Marseilles and Joliet and were fully withdrawn by mid-January 2026.19Capitol News Illinois. Judge Dismisses National Guard Mobilization Suit After Trump’s Loss at Supreme Court
On April 20, 2026, Judge Perry dismissed the lawsuit with prejudice as moot. All federalized Illinois Guard members had been demobilized, all out-of-state troops had left, and the original deployment orders were “defunct.” Perry rejected the Attorney General’s request to keep the case open based on the administration’s threats to return, finding Trump’s social media post about general crime control “not helpful enough” to keep the litigation alive. She also declined to issue an injunction against future federalization, noting Chicago was “calm” with no imminent threat of redeployment.20WTTW News. Judge Dismisses Lawsuit Challenging National Guard Deployment in Illinois21Chicago Tribune. Lawsuit National Guard Deployment Illinois
What the Ruling Means Going Forward
Because the Supreme Court read “regular forces” to mean the military, § 12406 is now a much narrower tool for domestic deployments. Combined with the Posse Comitatus Act, the ruling leaves a president who wants to use federalized Guard troops for law enforcement with limited options. The Insurrection Act remains a theoretical path, but invoking it would force the administration to abandon its earlier position that protective functions do not constitute “executing the laws.”22Just Security. Trump v. Illinois Supreme Court The dismissal with prejudice means this particular case is closed, but the Supreme Court’s statutory interpretation stands as controlling authority for the next time the question arises.