Senator Sinema made a calculated, self-serving political move. If she remained a Dem, she would have been primaried, and probably lost. As a Rep she would have alienated the Dems entirely, and, most likely still have lost in a general election. As an Independent she has set herself up to be courted by both sides. If she runs as an Independent, she would siphon votes from any Democrat candidate, ensuring that a Republican would win. The Dems have no choice but to align behind her candidacy. I don’t particularly like her, but it was a smart political move to keep her seat in '24.