Kyrsten Sinema has decided to make her unofficial status official, as Beege wrote earlier. The Arizona senator becomes the third independent in the upper chamber, but perhaps the only truly independent figure in the chamber. Both Bernie Sanders and Angus King identify as independent, but have rarely if ever bucked Chuck Schumer’s leadership during their entire tenures — especially to the center, as Sinema has done.

That raises another question about the only other member of Schumer’s caucus to follow that same pattern. And that question will only grow more acute for Joe Manchin as his own re-election date approaches. Manchin can’t win again in West Virginia as a Democrat, especially if Joe Biden ends up at the top of the ticket.

But can he win as an independent?

That’s not as easy a calculation as Sinema faced. In her case, as Philip Klein points out, progressives had made it clear that they would offer a robust primary challenge to Sinema in 2024. By opting out of the party, Sinema can sidestep that and force Democrats to decide whether they want to endorse her to prevent a general-election split, or fight her in November 2024 and hand the seat to the GOP:

Sinema’s action appears to be a preemptive strike. By acting now, she avoids having to go through a tough Democratic primary she could very well lose, and then face the decision of having to leave the party in a position of weakness. This way she gets ahead of the story and has more time to make her case to voters.

Keep in mind, when Lieberman became an independent, he did so after having already served three terms as senator, in a state that was much more Democratic than Arizona, and with an issue (the Iraq War) that motivated a lot of Republicans to cross over and vote for him. In that election, the Republican candidate ended up with less than 10 percent of the vote.

So clearly, Sinema wanted to get a head start in branding herself as an independent to Arizonans. Assuming she decides to run, Democrats will have to make a difficult decision as to whether to run their own candidate, and risk splitting the vote and losing the seat to a Republican, or accepting somebody who will vote with Democrats on most issues. A situation in which there’s Sinema as an independent as well as a Democratic candidate on the November ballot, is one in which you can see a Kari Lake get elected to the Senate.

Klein uses the Joe Lieberman-Ned Lamont fight as an analogue. It’s even better as a contrast. Connecticut is, and was at the time of the 2006 challenge, a deep-blue state. Democrats could afford to have that kind of fight in a general election there. (Alaska and Lisa Murkowski’s adventures would be a pretty good analogue to that on the Right, in fact.) Arizona, however, is a much more evenly split state — it’s barely purple at the moment. Republicans have blown chances in the last several cycles in statewide races, but they can win with good candidates and messaging focused on the concerns of Arizonans. Democrats can’t risk that split in Arizona the way they could in Connecticut at the time. And even then, it took Republicans to rescue Lieberman in the end.

In other words, Sinema’s prospective progressive challenger Rep. Ruben Gallego is likely the hardest hit in this announcement. He’s not happy about it, either.

Manchin faces the crisis of being in a state at the other end of the spectrum. Progressives threatened a primary challenge to Manchin too, but it’s an empty threat in a state as red as West Virginia. Manchin’s big problem is that he cut a deal with Schumer this year and then got stiffed on the concessions, the worst of both worlds for a man who argues that he delivers for his constituents no matter what his party ID says.

Would a flip to independent status help Manchin in next year’s re-election campaign? It might not hurt, but if he caucuses with Schumer, it’s not going to make much difference. Republicans will shred him either way, and dumping his Democrat status will allow Schumer and his party to cut off his funds for re-election. They’ll nominate an up-and-comer instead, one who has no chance of prevailing in 2024 but who can start building some name ID for rebuilding the Democrat Party in West Virginia in the future. Manchin still could flip to the GOP, but thanks to the Georgia runoff, it would stick him in the minority and out of any hope of a committee chair position.

However, there is one more possibility. What would happen if both Manchin and Sinema move into the Independent column — and refuse to caucus with either party initially? Instead of a 51/49 split in the Senate, it suddenly becomes 49/49/2; if King decides to join, then it becomes 49/48/3. That would force both caucuses to bargain for their support in a leadership fight, one that would keep Kamala Harris on the sidelines and require whomever wins to stick to their bargains. The two or three senators in the center would have far more power to dictate policy outcomes and to punish welchers than they do at present. If they get betrayed, the Independent caucus could trigger a leadership fight by swinging to the other side and starting the process all over again.

It would be the Manchin-Sinema Show of 2021-22 again, but on steroids. Furthermore, it suddenly makes both of their states the most important political ground in 2024, and that would make both senators indispensable to their voters. Short of flipping to the GOP outright, it’s the best argument Manchin would have for re-election in the next cycle.

That would take a lot of guts, but in truth, neither Manchin or Sinema really have anything to lose. If it succeeds, they may end up setting a trend that would either force an end to the partisan wars, at least until voters have their say about the direction of the country in 2024.