Trump should file a law suit against every person who signed that fake Russia collusion letter. He should sue them into a tent on some sidewalk. He has to pay rough now and this is the time.
Presuming you’re thinking libel, post NY Times v Sullivan in 1964 it’s hard for a politician to overcome the libeler’s 1st Amendment rights. I’ve had the same thought though many of Trump’s statements could be problematical in that climate. John Adam’s would put his political opponents in jail with the Alien and Sedition Acts. Still on the books.