We all thought that winning that 51st Senate seat meant Kyrsten Sinema would fade into the background.

Apparently not.

The centrist Arizona Senator announced on Friday morning that she was leaving the Democratic Party and registering as an Independent. According to Politico:

Arizona Sen. Kyrsten Sinema is changing her party affiliation to independent, delivering a jolt to Democrats’ narrow majority and Washington along with it.

In a 45-minute interview, the first-term senator told POLITICO that she will not caucus with Republicans and suggested that she intends to vote the same way she has for four years in the Senate. “Nothing will change about my values or my behavior,” she said.

And here is the nonsensical, pablum-filled video that Sinema released to explain her decision.

Sinema’s decision induced anger and panic among Democrats and a fair amount of schadenfreude among Republicans. Early analysis was confusing and Sinema remained typically opaque. Here’s my take on why she changed her affiliation and what it means.

This is Mostly NBD

Raphael Warnock’s reelection this week means Democrats now have a functional majority. Democrats can ignore McConnell on the organizing resolution, they have majorities on all of the committees and wield the power to send subpoenas without Republican consent.

Over the last couple of years, Mitch McConnell and other Republicans reportedly made numerous efforts to recruit Sinema. There has been a long-running fear that Sinema would join the Republican Caucus, with whom she sometimes votes and pals around.

That’s not what happened...