>>510053714 (OP)theoretically if they take control of the house, they could likely impeach him for something, just like they did during his first term. if they take control of the senate or there's even a trickle of bipartisan support in the senate, he could be removed.
this would be completely untested ground though, because the only other time it came this close, nixon resigned. how do you actually remove the president? then what, do you put the VP in his place? in this theoretical democrat house and senate, they probably won't accept vance either, and vance's replacement as VP has to be approved by both houses, as per the 25th amendment. the political theater of an impeachment and a removal of trump and/or vance if he becomes president would be unprecedented. they might as well just call a snap election or something to keep up the ante of throwing wrenches into the system.
the ultimate truth is trump is impeachable, because the bar for that is just having a democrat-led house that can get the articles of impeachment out there. him being removed would either take republican turncoating or a democrat majority in the senate, but even if he could be impeached and removed, the political theater and wrangling that might take place, on both sides, might not be worth the trouble unless they're 100% sure they can absolutely get what they want out of it, which is impossible to know