How was Pence complicit?
Why and how so?
Pence propagated the Big Lie by denying Biden won for months after the election with comments like 'we will see what happens', but even without that, Pence's name is too closely affiliated with Trump IMO.
A progressive party by definition has a far wider spectrum of opinions than a conservative policy, so the Democratic Party is used to supporting candidates they don't fully agree with.
Polls are showing 30% of the Republican Party will leave if the senate convicts DJT, but 9 GOP senators already support conviction and looking at donor behavior will suggest there is a large fraction of the party that won't stand for acquittal. Of course if they don't convict him, he still has the supporters to win primaries.