That's been my fear for some time. When Trump was running in 2016, he was quoted in an article telling his supporters that he was their last chance to prevent the final downfall of everything they believed in. A big part of their support for Trump is that they see him as their last chance to turn the clock back on all the social and cultural progress since the Sixties that they despise so much. If Congress does attempt to impeach him, or he loses in 2020, there's no telling what some of his more extreme supporters will do. Some of them are so far into Dale Gribble "deep state" conspiracy theories that they will never believe that Trump really lost the election, or that he should be impeached. Hopefully, cooler heads will prevail, and I don't think a majority of Trump voters would resort to violence, but a significant percentage might.