But how would 80 million Trump supporters really make things bad for Pence? Calling his office? Yelling at him when he's in public?

If Pence ends up confirming Biden, he'll be persona non grata with us but seeing how the GOP and the media operate, he'll be okay. Probably a prestige guest on FOX for as long as he wants, suddenly respected by the Left, and probably many years in Republican govt. although not as President.

I hope he doesn't but Pence could absolutely betray Trump.