I don't see anything (not even rampant election fraud) getting between Trump and the White house this time round. Ultimately succession has to be on the cards. California and Texas can't be in the same country much longer; and it'd have to be better than another civil war.
You are likely right, however a week can be a long time in politics let alone a month. I expect that the left will be screeching at anyone not supporting their new candidate when the "chosen one" is revealed. We'll all be getting called racists, misogynists' and bigots again soon enough.
I really hope you are wrong about the succession though. If the US divides like that it'll be the end of it as a super power and that would be very destabilizing globally.