The Supreme Court of the United States has ruled against President Donald Trump’s effort to federalize and deploy approximately 300 Illinois National Guard members to Chicago, where the administration sought to provide additional protection for Immigration and Customs Enforcement agents operating in the city. The decision centers on whether the president identified lawful authority to use military forces in this context, particularly in a state that has adopted sanctuary policies limiting cooperation with federal immigration enforcement.
The issue arose after the Trump administration moved in October to deploy National Guard troops to assist ICE agents amid reported unrest near immigration facilities in the Chicago area. A federal judge appointed by former President Joe Biden issued a temporary restraining order blocking the deployment. The administration appealed to the U.S. Court of Appeals for the Seventh Circuit, which declined to stay the judge’s order. The matter was then brought before the Supreme Court, with the administration asking the justices to allow the deployment while litigation continued.
On Tuesday, the Court denied the administration’s request in a 6–3 decision, concluding that the government had not demonstrated a valid legal basis for federalizing the Guard under the circumstances presented. In its unsigned order, the Court stated:
“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. If that is correct, it is hard to see how performing those functions could constitute ‘execut[ing] the laws’ under §12406(3). (‘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.”
Chief Justice John Roberts and Justices Sonia Sotomayor, Elena Kagan, Amy Coney Barrett, and Ketanji Brown Jackson were aligned with the Court’s order. Justice Brett Kavanaugh wrote a concurring opinion. Justices Samuel Alito and Clarence Thomas dissented, along with Justice Neil Gorsuch.
In his dissent, Justice Alito focused on the safety of federal officers, writing, “Whatever one may think about the current administration’s enforcement of the immigration laws or the way ICE has conducted its operations, the protection of federal officers from potentially lethal attacks should not be thwarted. I therefore respectfully dissent.”
The administration had argued that the deployment was necessary due to ongoing security concerns around ICE facilities. According to reporting cited in court filings, protesters and rioters have repeatedly gathered outside an ICE facility in Broadview, Illinois, where agents were attacked and demonstrators chanted threats, including “Kill ICE!” and “Shoot ICE!” These incidents formed part of the administration’s justification for seeking additional federal protection.
The ruling highlights the legal boundaries surrounding the use of military forces within U.S. states, particularly in domestic law enforcement contexts. The Posse Comitatus Act generally restricts the military from executing civilian laws unless Congress authorizes an exception. While presidents retain authority to protect federal property and personnel, the Court’s decision underscores that such actions must be clearly grounded in statutory authority when they involve federalizing state National Guard units.
The case, Trump v. Illinois, No. 25A443, now returns to lower courts for further proceedings. The decision leaves unresolved broader questions about how future administrations may respond to threats against federal officers operating in jurisdictions where state and local governments oppose federal enforcement priorities, an issue with implications for public safety, federal-state relations, and the scope of executive power.
