Is there something that Trump can do that would turn GOP congressmen against him? Or is the GOP congressmen unconditionally loyal to him? Does the congressional GOP approve of Russia then?
Leave office. If he leaves under a cloud, Trump supporters in Congress will become as rare as ardent Nazis in post-WWII Germany.
Short of that, nothing in the realm of things Trump is even remote likely to do that would turn more than a tiny fraction of the Congress against him. If fraud, sexual assault, obstruction of justice, on top of his incompetence and mythomania haven't done it, nothing will.
