Supreme Court Blocks Trump National Guard Deployment to Chicago, Ruling 'Regular Forces' Means Military

In a 6-3 decision representing the Trump administration’s first major Supreme Court defeat in months, the Court blocks President Trump’s attempt to deploy federalized National Guard troops to Chicago without gubernatorial consent. The ruling turns on a critical statutory interpretation: the phrase “regular forces” in 10 U.S.C. § 12406(3) likely refers to the U.S. military, not civilian law enforcement agencies like ICE. This means the president can only federalize the National Guard under this statute when the military itself is unable to execute the laws—circumstances the Court calls “exceptional” since the Posse Comitatus Act forbids military domestic law enforcement except when authorized by Congress or the Constitution. Chief Justice Roberts, Justices Barrett and Kavanaugh join the three liberal justices in the majority, over dissents from Justices Alito, Thomas, and Gorsuch.

The ruling’s intellectual foundation comes from Georgetown University law professor Martin S. Lederman, a former Justice Department Office of Legal Counsel attorney who submitted an amicus brief arguing the administration fundamentally misunderstood the statute. Lederman marshaled extensive historical evidence showing that whenever Congress discussed “regular forces” in relation to the militia, they meant the standing military. His weekend-written brief prompted the Court to request supplemental briefing on this specific question, and the majority ultimately adopted his interpretive framework wholesale.

Justice Kavanaugh writes a significant separate concurrence containing two notable elements. First, his footnote states the ruling “does not address the president’s authority under the Insurrection Act,” acknowledging Trump could potentially invoke that statute instead—though Lederman’s brief argues the Insurrection Act imposes even stricter requirements, traditionally requiring a governor’s request or federal court order enforcement. Second, and remarkably, Kavanaugh’s footnote 4 states that officers “must not make interior immigration stops or arrests based on race or ethnicity”—appearing to walk back his September 2025 position in Noem v. Vasquez Perdomo where he suggested race could be “a relevant factor” in immigration stops. Legal scholars note this apparent reversal may reflect sustained criticism of his earlier racial profiling stance.

The ruling will likely bolster similar challenges to National Guard deployments in California, Oregon, and other cities, establishing significant new limits on presidential authority to deploy military forces domestically without state consent. Justice Gorsuch’s dissent raises fundamental constitutional questions: “When, if ever, may the federal government deploy the professional military for domestic law enforcement purposes consistent with the Constitution?”