There are those in the GOP not very happy with the president right now. Says one highly placed PA GOP source, “It is amazing the damage Trump is doing to the Republican party at this point. The amazing thing is he is also solidifying his record in history. Historians will forget the tremendous economy before the policy successes and remember him as a president who with no evidence whatsoever cried Wolf. I personally know the federal judges who had his cases. The two that wrote opinions are rock solid conservatives…In normal circumstances since Biden won not because people voted for his platform but because enough people were voting against trump therefore 2022 would be an awesome year for Republican. However if Trump continues on his “election was stolen” song and immediately begins campaigning for 2024 he will put a cloud over the 2022 elections.”
Thus it is possible that the president, even though still the nominal head of the Republican Party, would suffer a Newton’s Third Law reaction inside the party. Tweets like this don’t help his case.
Biden can only enter the White House as President if he can prove that his ridiculous “80,000,000 votes” were not fraudulently or illegally obtained. When you see what happened in Detroit, Atlanta, Philadelphia & Milwaukee, massive voter fraud, he’s got a big unsolvable problem!
— Donald J. Trump (@realDonaldTrump) November 27, 2020 
That is not a statement, it’s a tantrum. It’s also legally incorrect and factually incorrect. And as the president is making these charges, the burden of proof falls on him, not Biden. Yes, Biden cheated. Yes, Biden won. Grow up and get over it. The Republican Party and the conservative movement are supposed to be the adult in the room, eschewing emotion for fact and realism. To abandon that position for the benefit of any politician is inexcusable.
If the president continues on this bitter ender path, instead of preparing to fight 2022 for congressional candidates, his stock could fall with party pros, the party faithful, and donors. But it will have little effect on his personal base, who are loyal to the man through anything. Ergo, if the GOP as an organization swings against the president, where would his base go?
These voters make up a majority of the Republican vote. If they left and formed a Populist Party, that would seem to be an accurate name for it, they would split the Republican vote in two and guarantee Democrat wins even without cheating.
Also, there inevitably will arise an anti-Trump GOP player. Perhaps not blatantly against the president, but with moderately different ideology, another base inside the party, and foremost, a different demeanor. They will not criticize the president directly. They will instead form an obvious contrast to him. Smart money there is on Nikki Haley. She could head the Republican loyalists left holding the bag after a party split.
What would a Populist Party look like? Based in the South, Midwest, and certain parts of the West, it would be a strange hybrid, combining Trump/Sanders trade protectionism with cultural conservatism and national security realism. The president would be its founder much like Teddy Roosevelt founded the Bull Moose Party. It would appeal to a rural and independent audience, and to some idealistic young voters. Even the threat of it could hold the GOP hostage. No doubt Donald Trump already has the same thought.