Leinenweber considered new restrictions placed on the grants in July.
The decision marks the latest in a swift turn of events. Throughout his presidential campaign, he vowed to pull federal funding from such cities unless they began cooperating and collaborating with Immigration and Customs Enforcement (ICE) to facilitate deportations.
The ruling from US District Judge William Orrick III in San Francisco said Trump's order targeted broad categories of federal funding for sanctuary governments, and that plaintiffs challenging the order were likely to succeed in proving it unconstitutional.
"Some states and cities have adopted policies created to frustrate the enforcement of our immigration laws", Sessions said. Trump later adopted a softer tone toward the 800,000 immigrants protected by DACA, telling them not to worry about being deported. In the months since taking office, he has moved to cut documented immigration in half, in addition to aggressively targeting undocumented immigrants.
The announcement came just days after a nationwide conversation about Dreamers, undocumented immigrants who were brought to the US illegally as children.
Trump on Friday took a hard line against allowing close family members of new immigrants to follow those immigrants to the U.S.
"To a degree perhaps unsurpassed by any other jurisdiction, the political leadership of Chicago has chosen deliberately and intentionally to adopt a policy that obstructs this country's lawful immigration system", Sessions said in a statement after the complaint was filed.
Those efforts haven't gone over well with Attorney General Jeff Sessions, who has sought to punish urban hubs failing to cooperate with federal immigration policy.
Like other sanctuary cities, Chicago has a longstanding policy of not sharing information with federal immigration authorities unless a suspect is charged or convicted of a serious crime. "This is astounding given the unprecedented violent crime surge in Chicago, with the number of murders in 2016 surpassing both NY and Los Angeles combined".
But that approach isn't seeing much sympathy in court.
The Justice Department grants at issue typically are used to help police improve crime-fighting techniques, buy new equipment and assist victims of crime.
A spokesman for the Department of Justice disagreed.
It means that at least for now, the Justice Department can't deny requests for public-safety grants from cities that refuse to impose Sessions' tough immigration policies.
At stake for Chicago is roughly $2.3 million from the Edward Byrne Memorial Justice Assistance Grant.