As an independent, Kyrsten Sinema can play spoiler to Democrats. That’s assuming she runs at all.

Kyrsten Sinema made official today what has been obvious for a long time: She’s not a Democrat.

The announcement is certainly not shocking — she ran in 2018 on her independent streak and has legislated that way — but it will have huge electoral ramifications if she chooses to run for reelection in 2024.

Most importantly, it paves the way for a Republican Party that has embarrassingly lost the past three U.S. Senate contests and has proven it would rather embrace extremism and batty conspiracies rather than competency and sanity to win back a Senate seat.

And maybe that’s exactly the leverage that Sinema hopes to use to keep Democrats at bay and retain her spot as one of the most consequential votes in the Senate. But, then again, this could all be window dressing for her to be a one-term-and-done senator who opts to run for something else — or leave the political arena altogether.

I don’t think there’s any doubt that the Republican field in 2024 will be similar to the 2022 field: A bunch of Donald Trump acolytes trying to out-MAGA each other and going to extremes that will make them nigh-unelectable in a state where voters are increasingly sick of the schtick. 

Republican primary voters, both here and across the country, will learn no lessons from the disastrous 2022 elections that saw Democrats keep the U.S. Senate and win important statewide contests. Losing in the U.S. Senate, governor, secretary of state and attorney general races in Arizona should be a wake-up call, but that would require a willingness to change that, let’s face it, the GOP doesn’t currently have.

As I wrote way back in January, Sinema understands this, and all of her actions in the Senate have been aimed at ensuring the center-right Republicans and independents who propelled her to victory in 2018 stay with her in 2024:

But her leaving the Democratic Party makes seismic shifts in gaming out 2024. Now, it’s not just about Sinema getting more liberal Democrats to hold their nose and vote for her over someone like Mark Lamb or Kari Lake, it’s a question of how she navigates a three-way race with another Democrat on the ballot.

While Sinema might have been able to hold the Democratic base as a Democrat — assuming she emerged from what was certain to be a bruising primary — doing so as an independent is exponentially more difficult.

We live in an age where partisan identity is becoming more of an immutable characteristic in politics, one that is increasingly difficult for candidates to overcome. The theory, as posited by political scientist Rachel Bitecofer, is that there is no “swing voter” who changes her mind every election and that election outcomes are instead purely a matter of who decides to vote.

The vast, vast majority of Republicans will vote for the GOP candidate, and the same is true of Democrats, while independents and unaffiliated voters in Arizona tend to lean toward Dems. The rule of thumb in a presidential year for a Democrat to have a path to victory in a two-way race in the Grand Canyon State is to hold 95% of Democratic voters, peel away 5% of GOP voters and nab 55% of independents.

But a three-way race scrambles those numbers, and puts Sinema in a position where her only (slim) chance to (maybe) win is to drive any serious Democratic challengers away. That would at least give her a conceivable shot at keeping some of those Democratic voters in the fold, though breaking through partisan identity is easier said than done — and only getting tougher as American politics becomes more and more polarized and tribal.

And given recent polling, Sinema is deeply unpopular in Arizona: A September poll by AARP found no constituency liked her, a shocking turnaround from just four years earlier when she won the election.

That all assumes she can keep serious Democratic candidates — people like U.S. Reps. Ruben Gallego or Greg Stanton — out of the race. Even in optimal circumstances, with the party behind an independent candidate, that is dicey. But after repeatedly punching Democrats in the gut for the past two years, the party infrastructure won’t lift a finger to help Sinema.

Her moving to an independent is far more harmful to the Democrats than it is the Republicans, of that there is no doubt. Suddenly, the Democratic nominee would have to fight Sinema to win those disaffected soft Republican voters and right-leaning independents. 

But I think it’s all for naught. Those with knowledge of private campaign polling say Sinema had torpedoed her chances at winning in the 2024 primary by, over and over again, telling Democrats she wasn’t one of them and wouldn’t stand with them on core issues. 

This move to be an independent strikes me as the first step in the next phase of her public life, not a serious move to win reelection in a hyper partisan political climate where the R or D after a candidate’s name is shorthand for voters who have already made up their minds. Whatever else she is, Sinema is a brilliant tactician and a canny political operator. She knows exactly how difficult a statewide three-way race as an independent will be.

Sinema has a constituency of one, and this is the ultimate selfish move in catering to her belief that she is uniquely qualified to be at the center of American governance. And when the clock runs out on that, she’ll use it to capitalize on the next opportunity.