A federal judge in Chicago issued a temporary restraining order (TRO) on Thursday to prevent the deployment of the National Guard in the city.

April Perry, district judge for the Northern District of Illinois, enjoined the defendants (excepting President Trump) from “ordering the federalization and deployment of the National Guard of the United States within Illinois.” In an oral ruling, Perry said that there is “no credible evidence that there is danger of rebellion in the state of Illinois” or that the president cannot “execute the laws of the United States.” The TRO expires on October 23. A hearing will be held on October 22 to determine whether the TRO should be extended for a further 14 days.

The state of Illinois filed a complaint for emergency, declaratory and injunctive relief against the Trump administration on October 6. The complaint was filed in response to Secretary of Defense (“Secretary of War”) Pete Hegseth’s attempt to federalize the Illinois and Texas National Guards on October 4 and 5. The complaint described Secretary Hegseth’s actions as “illegal, dangerous, and unconstitutional” and stated that federal use of the National Guard “infringes on Illinois’s sovereignty and right to self-governance.” It stated that his actions do not satisfy the three prerequisites for federalization under 10 U.S.C. 12406: 1) invasion by a foreign nation, 2) rebellion against the government, or 3) inability to execute the laws of the US with regular forces. It further claimed that the defendants violated the Posse Comitatus Act, the Administrative Procedure Act, and provisions of the Constitution. The Trump administration has filed a notice of appeal.

The National Guard is a part of the armed forces, and has been used to respond to domestic crises. It can operate on both state and federal levels, but is usually directed by a state’s governor.

Trump has signaled many times that he intends to use the National Guard to address violence in cities across the US. He has deployed forces in Los Angeles, DC, and Portland, citing the threats of crime, homelessness, domestic terrorism and protests against mass deportation. Numerous legal challenges have been mounted by states. The Ninth Circuit Court of Appeals is currently reviewing a TRO issued by a district judge in Oregon against deployment of the National Guard in Portland, which will have broader implications for the President’s power to deploy federal forces against states’ wishes.