Nope, he shouldn’t concede and he should continue his lawsuit to prove fraud even after he is out of office. He should take that all the way to a jury trial.
Oh, I'm pretty sure he'll get his trial, maybe more than one. As a defendant, of course. Unless he settles or enters a plea bargain. He'll never have another good day.
LOL It could very well happen. Might well indeed be a rough sledding for him after he departs Washington-financial, cilvil and/or criminal.
