There was polling of Republicans in January where 54% said they supported party over Trump, and 36% said they supported Trump over the party. A solid majority of Republicans still firmly believe the big lie DESPITE NO FUCKING EVIDENCE WHATSOEVER.
The rightwing backlash to a Mitt nomination would be ****LOUD****. They do not forgive him for his impeachment vote. If he's the nominee, either a huge % of their voters will stay home, or (more likely) we'd get a Trumpkin (or Trump himself) as a 3rd party candidate.
Republicans cannot win national elections without the lunatics that make up somewhere between 35-50% of their voters, and it's scary to consider the ramifications of that.
The only actual issues that they have real-world policy proposals for are banning abortion and scapegoating immigrants. It's been 25+ fucking years since they actually talked about fixing healthcare. I don't hear meaningful proposals for helping the middle class, addressing wild income disparities, educating children, or articulating a coherent foreign policy.
For a solid fucking decade now, conservative media ignores nearly every real issue in favor of Seth Rich, pizzagate, birthers, bamboo ballots, Hunter's laptop, relentless anti-Fauci conspiracies, more Hunter's laptop, Jewish space lasers, Tucker Carlson's open white supremacy, "hey look, let's imagine we found more imaginary things on that imaginary laptop," and jaw-dropping levels of stupidity from the My Pillow guy.... all of whom have banded together to accuse anyone who opposes them of grooming children.
Those people are abso-fucking-lutely not voting for Mitt.