The City's lawsuit will argue that the Justice Department can not make grants contingent on these requirements because they would "effectively federalize local detention facilities" and violate the Fourth Amendment of the U.S. Constitution in requiring detainees to be held beyond the timeframe in which they would otherwise be eligible for release.
City officials said complying with the new requirements, to get federal money, would violate Chicago's "Welcoming City" ordinance - a law which prohibits the CPD from giving federal officials access to people in custody, bans ICE agents from police facilities for interrogations and bars cops from sharing immigration status information.
CHICAGO, IL - JUNE 26: Chicago Mayor Rahm Emanuel speaks during a press conference to announce the use of a mobile ballistics lab being operated by the Bureau of Alcohol Tabaco and Firearms (ATF) in Chicago to help process ballistic evidence at crime scenes on June 26, 2017 in Chicago, Illinois. Emanuel's message is viewed as politically advantageous in an overwhelmingly Democratic city with a minimal number of Trump supporters and a significant Latino population.
Missing out on the federal Edward Byrne Memorial Justice Assistance Grants could potentially cost sanctuary cities millions of dollars.
Mario Cantone's Scaramucci Signs Off 'The President Show' with Trump Makeout Session
When asked about the possibility, he told TMZ: "I don't know how to dance". But there were still hiccups. "You never know who will be beheaded next".
For one, Sessions will be requiring police stations to give 24-7 access to immigration and customs enforcement.
Emanuel said Sunday that Chicago won't "be blackmailed" into changing its values as a welcoming city.
The city stands to lose about $3.2m under the new policy. But Emanuel said the equipment they buy is "needed" and called the effort to pull those grants "the camel's nose under the tent".
"So-called "sanctuary" policies make all of us less safe because they intentionally undermine our laws and protect illegal aliens who have committed crimes", Sessions was quoted as saying in a July statement telegraphing the conditions. Chicago had 50 more homicides than NY and Los Angeles combined through mid-June, even though it is far less populous than both.