Right now, there’s a discussion about whether decent people should leave the Republican party. I’m not sure the implications have been fully considered.
Personally, I’m remaining a Republican in order to be able to vote for better candidates in future primaries. In the American political system, Moderates can have more impact by voting in primaries than by just voting in the general election. Ten million people voting for an independent party won’t help the party win, but five million people voting in the Democratic or Republican primaries would be an important constituency. Just under 37 million people voted in the 2020 Democratic presidential primaries, and turnout is much lower for other races. There’s certainly an argument that center-right people who don’t like Trump should stay in the Republican party so that there’s some kind of Anti-Trump constituency during the primaries. If the moderates and people who care about truth or standards of behavior leave, that makes it easier for the party to nominate mendacious nutjobs.
Another route would be for Republicans who don’t like Trump to create a third party. However, I suspect that moderates would also be temperamentally unlikely to do something radical like form a new party. If there is a new party it would probably come from people who think Democrats aren’t left-wing enough, or that Republicans aren’t right-wing enough. The main consequence of a third party is to split the vote. For obvious reasons, Democrats would like a center-right third party taking votes from Republicans, and might be happy in the unlikely scenario when a new center-right party replaces Republicans, but this drawbacks for anyone who likes conservative policy.
The final option would be for the center-right to join the Democratic Party. Let’s consider the implications of that, with five million conservatives who don’t like Trump (three million voters Gary Johnson gained in 2016 plus two million Romney- Clinton voters) joining the Democrats. The 2020 Democratic primary did have 36,917,179 votes, so an influx of a few million conservatives wouldn’t always be enough to determine the winner, but it would shake things up. This would not be the equivalent of Operation Chaos, or any moves by Republicans to organize in Democratic primaries to support someone seen as unelectable. In this case, when voters on the center-right would vote in Democratic primaries, we wouldn’t be voting to sabotage Democrats. We would be voting for our preferred candidate.
If Republicans dissatisfied with the Trump administration and the publicity garnered by the likes of Marjorie Taylor Greene (primarily in the mainstream media) stay in the party, they have the advantage of primaries where it’s more consequential, and in the event that Republicans nominate a flawed candidate and Democrats nominate a better one, they can vote for the Democrat in the general election. It seems pretty unlikely that Republican defections lacked an impact. The decision in Wisconsin (the tipping point state) was made by less than a percent. If 0.4% of voters nationwide had gone for Trump instead of Biden, Trump would have been reelected. So small differences really mattered.