Washington (CNN) Attorney General Jeff Sessions and the Trump administration were handed another stark defeat in their effort to punish sanctuary cities, with a judge declaring a law the administration had been relying on unconstitutional.

In a terse 58-page opinion, a Reagan-nominated district court judge thoroughly rebuked Sessions' efforts to penalize sanctuary cities, saying efforts he has taken to impose immigration-related conditions on federal law enforcement grants are unconstitutional. The judge also called the underlying law that the administration has pointed to as justifying its efforts unconstitutional.

The ruling will only apply to the city of Chicago for now -- but the judge said he intends for his ruling to apply nationwide.

Judge Harry Leinenweber had also previously temporarily blocked the grant conditions, which the appellate court upheld.

But now Leinenweber has gone even further — making his initial ruling permanent and going beyond it to strike down the underlying law, referred to as Section 1373.

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