In what is at least a temporary victory for cities that have defied Sessions, U.S. District Judge Harry Leinenweber ruled that the Justice Department could not impose the requirements.
He said the city of Chicago had shown a "likelihood of success" in arguing that Sessions exceeded his authority with the new conditions. Among them are requirements that cities notify immigration agents when someone in the country illegally is about to be released from local jails and to allow agents access to the jails.
The ruling came after Chicago had asked the judge for a "nationwide" temporary injunction this week, asking the judge not to allow the Justice Department to impose the requirements until the city's lawsuit against the department plays out in court.
Chicago officials have said such a ruling would prevent the Justice Department from withholding what are called Edward Byrne Memorial Justice Assistance Grants to the cities based on their refusal to take the steps Sessions ordered.
Philadelphia also sued Sessions over the same grants.
The ruling is another blow to Sessions, a longtime champion of tougher immigration laws. Earlier this month, Sessions announced that the administration would end a program that protects young immigrants who were brought to the U.S. illegally as children or came with families who overstayed their visas. Trump later announced he was working on an agreement to protect them.
Whether or not the ruling means that Leinenweber will ultimately decide in favor of the city is unclear.
During a hearing, Ron Safer, an attorney representing the city, said that if the Justice Department prevailed, he could use the same argument to "seize" even more authority to tie grant money to doing what he wants.
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