The Supreme Court has denied President Donald Trump’s request to send the National Guard to Chicago to protect ICE agents, a decision that could jeopardize similar deployments in other cities.

On Dec. 23, the court denied Trump’s deployment request, with conservative Justices Samuel Alito, Clarence Thomas, and Neil Gorsuch dissenting, a rare setback for the administration on the conservative court’s emergency docket, CNN reports.

“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 court said in its unsigned order.

Federal law allows a president to federalize the National Guard when “regular forces” are insufficient to enforce U.S. laws. During the case, a debate arose over whether “regular forces” referred to the military or to federal agents, such as those from ICE. In its ruling, the court indicated the term likely refers to the military and noted that the law Trump invoked “likely applies only where the military could legally enforce the laws,” meaning it does not extend to protecting immigration agents.

“Thus, at least in this posture, the government has not carried its burden to show that’ the law at issue in the case, ‘permits the president to federalize the guard in the exercise of inherent authority to protect federal personnel and property in Illinois,” the court said.

Source: Supreme Court Blocks Trump’s Push For National Guard Deployment To Chicago