SINEMA SAVES HER CAREER AND TRIES TO MAKE IT LOOK LIKE PRINCIPLE -- BUT WHY NOW?

Senator Kyrsten Sinema has announced that she's a registered independent now. In an Arizona Republic op-ed, she says she's "declaring my independence from the broken partisan system in Washington," but it's clear why she really left the Democratic Party:

Switching parties allows Sinema to avoid a brutal primary challenge, or at least make one much more difficult to pull off. If another Democrat decided to jump into the race, they could risk splitting the vote in the general election and handing Republicans the seat in 2024.

She's not popular among Arizona Democrats, and would probably lose a primary to (in all likelihood) Congressman Ruben Gallego, who just won reelection by 54 points. But now Democrats will be motivated not to run a candidate against her, because they know Republican voters are likely to vote the party line, and they don't want a split the liberal/moderate vote and put Doug Ducey or Kari Lake in the Senate.

Sinema is forcing Democrats to stick with her even though they want to be rid of her. It's like (SPOILER ALERT) the end of Gone Girl.

But why now? She could have made the announcement anytime before the start of the 2024 campaign. A state "sore loser" law prevents her from running in the Democratic primary and then running as an independent in the general election, so she'd have to make the choice at the outset of the campaign. But she didn't need to make it now.

She insists that she won't be switching caucuses:

In a 45-minute interview, the first-term senator told POLITICO that she will not caucus with Republicans....

But will she caucus with Democrats? CNN says more or less, probably:

Democrats will have a narrow 51-49 majority that includes two independents who caucus with them: Sens. Bernie Sanders of Vermont and Angus King of Maine.

While Sanders and King formally caucus with Democrats, Sinema declined to explicitly say that she would do the same. She did note, however, that she expects to keep her committee assignments – a signal that she doesn’t plan to upend the Senate composition, since Senate Majority Leader Chuck Schumer controls committee rosters for Democrats.

With a 51-49 majority, Democrats maintain control over Senate committees. They can appoint the majority of committee members and have control over subpoenas. Sinema now threatens that. She can take that power away from the Democrats at any time.

But she could have done that anyway. So this could be just a pure branding exercise -- or it could be a sign that she's going to vote more often with Republicans than she does now, which isn't as often as you think:

FiveThirtyEight calculates that she votes with President Joe Biden 93 percent of the time, more than [Joe] Manchin, Jon Tester of Montana, Jacky Rosen and Catherine Cortez Masto of Nevada, and Bernie Sanders of Vermont, an independent who caucuses with the Democrats. These percentages can be misleading, because not all votes carry equal weight. But consider judicial nominations, perhaps the most important thing for Democrats over the next two years. Sinema voted to confirm Justice Ketanji Brown Jackson, and as of February, she hadn’t voted against a single Biden bench nominee.

Her real value to the right -- particularly to her corporate-lobbyist pals -- has been her ability to prevent legislation from coming to the floor altogether, so maybe her voting record isn't a true measure of what she does as a senator. But I think this will liberate her to be more overtly right-wing. So I'm really sorry the Democrats couldn't manage 52 wins.