In July 2017, the United States Attorney General announced new conditions for the Edward Byrne Memorial Justice Assistance Grant (JAG) Program, a primary source of federal funding for local law enforcement. The Department of Justice (DOJ) stipulated that to receive these funds, state and local governments must allow federal immigration officials access to detention facilities and provide advance notice before releasing individuals suspected of immigration violations. This policy targeted "sanctuary cities" that limit cooperation with federal immigration enforcement.

Several cities, including Chicago and Philadelphia, sued the DOJ. They argued that the Attorney General lacked the authority to impose new conditions on grant funding that Congress had not explicitly authorized. The cities contended that under the Constitution, the power to appropriate funds and set conditions for their use belongs to Congress, not the Executive Branch. Additionally, the cities argued that the federal government was attempting to "commandeer" local police forces to enforce federal regulatory programs, a violation of the Tenth Amendment. In 2018, the U.S. Court of Appeals for the Third Circuit ruled in favor of Philadelphia, stating that the Executive Branch could not withhold congressionally appropriated funds based on conditions not approved by Congress.