When you get your security clearance, if you then reveal the contents of a classified document, I think you are subject to vastly increased penalties. I think this new requirement is to ensure the lawyers can’t talk about any of the evidence to the press.
What lawyer hasn’t got something to hide from a security clearance backround check?
Good luck finding one cleaner than Caesar’s wife.
This will scare off anyone with anything to hide who doesn’t want their dirty laundry aired for all to see.
The court can just impose a gag order to prevent talking to the press. Requiring security clearance means the same people prosecuting Trump have veto power over who his lawyers can be.