Because it isn't a criminal trial, it is all political. a President can be impeached over anything. Get enough people together they can impeach him for his stupid hair, they have been trying to nail him with a gotcha before he was even in office instead of doing their jobs. Right now the House sitting on the impeachment papers in an attempt to negotiate is hilarious, They have no power over the Senate, the Senate could probably have their own vote or be real dicks about it and have everybody back in DC for weeks upon weeks dealing with this crap, instead of out there on the campaign trail. Hell this entire thing is because of some shit Joe Biden did. Ol' Blood Eye is gonna sniff ya real good!