The key line from her explanation: “After watching the debates and seeing everything, Sinema’s stance on a lot of things are very close to mine.” You don’t say.

Were there actually progressives in Arizona who were so fooled by Sinema’s new inch-thin “centrist” facade after years spent as a left-wing activist that they were leaning Green instead? There are like 800 clips of her sneering at Arizona’s conservative policies in years past; she’s not Joe Manchin, no matter how convenient it is right now for her to pretend that she is. If you believe most of the polls, in fact, the answer is no — few progressives were fooled. In three of the last four taken, Angela Green has received just one or two percent of the vote. Which is what you’d expect in a very tight race in a reddish state in 2018. Left-wingers understand that their only chance of stealing this seat and possibly handing Chuck Schumer a majority in the Senate is if all hands are on deck for Sinema, the Democratic nominee. Green dropping out and endorsing doesn’t give her much.

But it gives her something, and considering how ridiculously tight this race has become, it might be enough to matter. Also, I said “most” of the polls see Green as a nonfactor in the race, not all of them. Here’s a noteworthy exception from NBC released just a few days ago:

Hoo boy. If Green really is pulling anything like six percent, her dropping out and endorsing Sinema is likely the kiss of death for McSally. On the other hand, if McSally really is pulling anything as dismal as 44 percent of the vote, she’s likely dead no matter what Green does. The good news is that the other three-way polls of Arizona taken this month have her doing better than that — 47, 48, and 52(!) percent, respectively. She led in all three of them. Meanwhile, Sinema has led in three of the last four head-to-head polls and was tied in the fourth, suggesting that Green’s endorsement really might matter. There’s no Senate race in the country that’s more of a black box right now than Arizona, where either candidate winning very narrow or fairly comfortably (e.g., five points or so) seems entirely plausible.

There’s one more wrinkle. Arizona allows for voting by mail, and most voters avail themselves of that convenience. Apparently, 60 percent had already sent in their ballots before Green announced she was withdrawing and backing Sinema. Imagine if McSally wins a nailbiter because Green dragged her feet in encouraging her supporters to vote for the Democrat instead. On the one hand, some Green Party voters are passionately left-wing and might have voted early, to signal their eagerness in rejecting the establishment Democratic candidate. On the other hand, other Green voters are stragglers, people who make up their minds at the last second and, under normal circumstances, might opt for the Green candidate simply as a protest vote. Those people might be affected by Green’s endorsement — but it’s too late for people in the first group. Early voting is garbage but it might work to the GOP’s advantage in this case.