A group of 25 bipartisan former governors filed an amicus brief with the U.S. Supreme Court on Monday opposing President Donald Trump’s attempt to deploy federalized National Guard troops in Illinois, warning that the administration’s actions threaten the constitutional balance between state and federal authority and set a dangerous precedent for executive power.
The brief, submitted in the case Trump v. Illinois (No. 25A443), urges the Supreme Court to deny the Trump administration’s application for a stay of lower court orders that blocked the deployment of National Guard members in the Chicago area. The former governors argue that the president’s unilateral federalization of the Illinois National Guard without consultation or consent from Governor JB Pritzker “disturbs the constitutional balance of state and federal authority, weakens state executives’ authority to maintain intrastate law and order, deprives states of vital emergency response tools, and breaks with a long tradition of cooperation between the federal government and the states on issues of public safety.”
The legal battle stems from President Trump’s October 4 decision to federalize and deploy up to 300 members of the Illinois National Guard to the Chicago area as part of “Operation Midway Blitz,” a multi-state immigration enforcement initiative. The administration invoked authority under 10 U.S.C. § 12406, claiming that violent assaults against federal immigration agents at protests near the Broadview ICE facility necessitated military intervention.
Illinois Governor Pritzker opposed the deployment, and the state, along with the City of Chicago, filed suit challenging the action as unconstitutional. U.S. District Judge April Perry issued a temporary restraining order on October 9 blocking both the federalization and deployment, finding insufficient evidence of “rebellion” or proof that regular federal forces were unable to execute the laws. The Seventh Circuit Court of Appeals partially upheld that decision on October 16, allowing the Guard to remain federalized but prohibiting its deployment within Illinois.
The Trump administration then appealed to the Supreme Court on Friday, with Solicitor General D. John Sauer arguing that the lower court order “countermands the exercise of the President’s Commander-in-Chief authority” and creates “intolerable risks to the lives and safety of federal personnel.”
The amicus brief was filed by a bipartisan coalition spanning multiple decades and political affiliations, including Democrats Jerry Brown (California), Steve Bullock (Montana), Jennifer Granholm (Michigan), Janet Napolitano (Arizona), and Republicans Arne Carlson (Minnesota), Bill Graves (Kansas), Marc Racicot (Montana), and Bill Weld (Massachusetts).
The former governors emphasize that the Constitution’s federalist structure divides authority between state and federal governments, with states retaining broad “police powers” to protect public health and safety—authority the federal government lacks. They argue that this balance, established at the Founding, is essential to preventing tyranny and protecting liberty.
The brief highlights that throughout American history, presidents have rarely federalized National Guard units without gubernatorial consent, and when they have, it occurred only under extraordinary circumstances—such as when governors openly defied federal court orders during the civil rights era. President Eisenhower federalized the Arkansas National Guard in 1957 only after Governor Orval Faubus refused to comply with a court order to integrate Little Rock Central High School, and President Johnson did the same in Alabama in 1965 after Governor George Wallace refused to protect civil rights marchers in Selma.
Critically, the brief notes that in both historical cases, presidents invoked the Insurrection Act—not 10 U.S.C. § 12406, the statute Trump relies on here. Furthermore, Illinois authorities have not defied any federal law; instead, they have “actively worked and cooperated with federal law enforcement to maintain order at the site of the modest protests in Broadview, while also allowing protestors to safely exercise their free speech rights.”
Drawing on their collective experience managing natural disasters, civil unrest, and public health emergencies, the former governors warn that the unilateral deployment threatens public safety in multiple ways. The federalization diverts hundreds of Illinois National Guard members from their regular state duties, including emergency response to natural disasters, creating “a real risk to the health and safety of Illinois residents.”
The brief also warns that deploying federalized Guard members without coordination with state and local law enforcement “will only exacerbate tensions in Chicago and thereby increase the risk to civilians and law enforcement officers alike”. They note that local law enforcement agencies are “best equipped to respond to issues that arise in connection with local protests, and to safeguard the constitutional rights of those who exercise their right to protest peacefully.”
The former governors argue that the Trump administration’s interpretation of 10 U.S.C. § 12406 conflicts with the statute’s language and historical practice. Section 12406 provides conditional authority triggered only by rebellion, invasion, or the inability to enforce federal law using regular forces—not unlimited discretion for the president to deploy Guard forces “anywhere, anytime, based on whatever facts that the president, in his sole discretion, deems sufficient.”
The brief emphasizes that when Congress intends to grant unreviewable presidential discretion, it uses “unmistakable language”—language absent from Section 12406. Unlike immigration or foreign policy contexts where executive power is strongest, the Constitution contemplates shared authority over state militias.
The amicus brief stresses that courts have a critical role in protecting the constitutional balance between state and federal authority, particularly when one sovereign encroaches on another’s power to maintain domestic order.
The Supreme Court has ordered Illinois and the City of Chicago to file their response to the Trump administration’s stay application by 5 p.m. EDT on Monday, October 20—signaling the justices could act quickly on the emergency request. The case was assigned to Justice Amy Coney Barrett, who oversees the Seventh Circuit.
Meanwhile, tensions continue in the Chicago area. Protests have persisted outside the Broadview ICE facility, with 15 arrests made on Friday. A federal judge has expressed “profound concern” that federal agents may be violating restrictions on the use of tear gas and has ordered all agents working under Operation Midway Blitz who have been issued body cameras to wear them during operations. CBP (Customs and Border Protection) Deputy Incident Commander Kyle Harvick and Shawn Byers, ICE Deputy Field Office Director, have been ordered to appear in court on Monday to explain reports of tear gas deployment without warning.
The former governors conclude their brief by urging the Supreme Court to deny the stay application, arguing that “the president’s assertion of authority to deploy military troops on domestic soil based on his unreviewable discretion, and without the cooperation and coordination of state authorities, threatens to upset the delicate balance of state and federal authority that underlies our constitutional order.”
