I'm not sure about impeachment - but I do think that's the most likely outcome is Trump derailing his own Presidency with injudicious remarks. Bill Clinton lost two years of his legislative programme due to the furore created by a comment he made about gays in the military while out jogging at dawn.

I'd say that it's more or less inevitable that Trump is going to say something on Twitter that is going to blow up in his face in a big way. People are able to say all sorts of things when they're running for the Candidacy / Presidency (H Clinton the first time round had several such mishaps). Do that when you're President and there's a good chance you'll run out of political capital before you've managed to achieve anything meaningful.