Whoever leaked it is almost guaranteed to have violated the CFAA. I'd bet any amount of money that the leaker signed a legally binding NDA as a condition of their employment. I'm not sure how information is classified at the Supreme Court, but I'm guessing it's marked Confidential. IANAL, but I'm sure there's plenty of other things to throw at them as well. What, they think making it "more illegal" is going to do anything?
They need to do what they do would for a leak in the defense or intelligence community, and get a team of CI guys in there to do their fucking jobs.