Rep. Elise Stefanik (R-NY), previously a moderate, became a flaming Trumper and it worked like magic, propelling her into the House leadership. Since she was worshipping Donald Trump at every turn, he decided to appoint her as ambassador to the United Nations, a position she very much wanted so she could tell all those countries how great Trump is—and add some foreign policy experience to her CV for a possible campaign for higher office. Unfortunately, with the House now being 220R, 213D and two (Democratic) vacancies, Speaker Mike Johnson (R-LA) can afford only three Republicans going rogue on him—four is fatal if the Democrats stick together. When the Big Bill containing all of Trump's priorities comes to a vote, Rep. Thomas Massie (R-KY) is a hard "no," Rep. Victoria Spartz (R-IN) is a probable "no," and Rep. Chip Roy (R-TX) is a possible "no," so Stefanik's vote might be needed to pass the bill.
For this reason, Trump pulled the plug on Stefanik's nomination. She can't go back to her old leadership position, because with Johnson expecting her to resign from the House momentarily, he gave her leadership slot to Rep. Lisa McClain (R-MI) and McClain does not want to give it back. So Trump's machinations caused Stefanik's career to look like this:
Backbencher → #3 in Republican caucus → Nominee for U.N. ambassador → Backbencher
Stefanik is not a happy camper being made a backbencher again. She doesn't see much of an opportunity to advance in the House, even though Johnson tried to create a new "leadership" post for her, so she is now seriously considering running for governor of New York State next year.
Republicans are petrified. They had expected that Rep. Mike Lawler (R-NY), a moderate, would cruise to the nomination and have a decent shot at unseating the not-terribly-popular Gov. Kathy Hochul (D-NY). What they absolutely do not want is a bitter ideological primary with a real possibility of an unelectable fire-breathing Trumper winning it. That would throw away a genuine chance at flipping the governor's mansion in a very blue state, not something that happens every day.
Stefanik hasn't declared yet, but if she wants a promotion, running for governor against an unpopular incumbent is probably her best shot. She could wait until 2028 and run for the Senate, but her opponent then would probably be either Sen. Chuck Schumer (D-NY) or Rep. Alexandria Ocasio-Cortez (D-NY), both of whom are far more popular than Hochul. Republicans will probably ask Stefanik to be a "team player," but she is probably not in much of a mood to hear that after what they did to her. (V)