A few days ago Joe Biden allowed as he was worried that Trump would steal the election, though he was fairly sure that if Trump refused to leave the White House, the military would not back him up.
Nonetheless, the legitimate fear exists that Trump will refuse to accept defeat. It would seem that it would be a no-brainer that Democrats should be confronting every Republican candidate with this question or some more clever variant thereof: will you oppose Donald Trump if he refuses to accept the results of the November election?
We’ve recently seen Republicans ducking questions about Trump’s tweets, etc. My guess is that they’d duck this question too, and if they do, those evasions should be used against them.