The city of Chicago will sue the Trump administration over its threat to cut off certain federal funding to so-called sanctuary cities that provide asylum to illegal immigrants.
Democratic Mayor Rahm Emanuel said the city will file its suit Monday.
"Chicago will not let our police officers become political pawns in a debate," Emanuel said at a news conference on Sunday. "Chicago will not let our residents have their fundamental rights isolated and violated. And Chicago will never relinquish our status as a welcoming city."
U.S. Attorney General Jeff Sessions has said the Justice Department will withhold a justice assistance grant from cities that fail to comply with new requirements related to immigration. Municipalities known as sanctuary cities are those that refuse to cooperate with federal requests to detain and hold noncitizens under arrest on charges unrelated to their immigration status, until immigration enforcement officers can take custody and possibly deport them.
Chicago has used justice assistance grants in the past to buy equipment for its police department. Sessions announced that any city applying for the program this year must meet new requirements: The should allow Homeland Security officers to enter jails and inquire about inmates' citizenship, and they also would be required to notify federal officers 48 hours before any suspected immigration violator is released from local custody.
The Chicago lawsuit is expected to argue that the Justice Department would be federalizing local jails and requiring city authorities to violate the Fourth Amendment of the Constitution, which requires probable cause for an arrest and blocks what it calls unreasonable search and seizure.
The Justice Department has not commented on Chicago's planned legal action.
Sessions has said the actions of sanctuary cities are "designed to frustrate the enforcement of our immigration laws." Mayor Emanuel has answered the attorney general by defending Chicago as a "welcoming city," one that encourages all of its residents to cooperate with police.
Rather than frustrating law enforcement, as Sessions alleged, a spokesman for Emanuel said Chicago "promotes public safety by ensuring that no city resident, regardless of their status, is afraid to cooperate with law enforcement, report criminal activity to the police, serve as a witness in court or seek help as a victim of crime."
President Donald Trump has made immigration reform one of the key goals of administration, arguing that undocumented migrants are making the U.S. less safe. His proposals include building a wall along U.S.-Mexican border and expanding requirements for those who want to emigrate to the U.S. legally.
A federal judge has already blocked a presidential executive order excluding sanctuary cities from consideration for any federal funding assistance. On the separate issue of Trump's attempt to ban for the time being all immigrants from six Muslim-majority countries, the Supreme Court has agreed to hear arguments on the case during the coming weeks.