We may be much closer to endgame in this race than anyone could have dreamed a week ago. And not endgame for Bernie, either.

In the March 4-5 poll, released on Thursday, 55% of registered Democrats and Democratic-leaning independents said they would support Biden for the Democratic nomination if the only other choice was U.S. Senator Bernie Sanders of Vermont. Another 45% said they would vote for Sanders.

Biden is again considered to be the candidate with the best shot at beating Trump. When the poll asked which of the presidential contenders is the most electable, twice as many Democrats picked Biden as those who picked Sanders.

Last week, the poll showed Sanders was considered the most electable candidate.

A 55/45 deficit with Warren out and her voters now free agents is a bad number for Bernie. The crosstabs at Reuters suggest that he is indeed the top second choice of Democratic Warren voters, but only by a 30/25 margin over Biden. Factor in independents who had Warren as their first choice and it’s just 47/46 for Bernie. There’s also a healthy contingent that named “other” as its second choice, which presumably means the centrists Buttigieg, Klobuchar, or Bloomberg. Which way do you suppose those voters will tilt when forced to choose between centrist Joe Biden and socialist Bernie Sanders?

There’s an X factor here, of course: Warren hasn’t endorsed yet and she’s quite likely to endorse Bernie when she does. That might move some of her fans who prefer Joe into Sanders’s column, which will narrow the gap. Even if she can convince two-thirds of her fans to support Bernie, though, how much will that matter?

To see, let’s look at the latest poll from Michigan. Bernie led by nine points in a poll taken there in mid-February, an auspicious sign given the momentous upset he pulled on Clinton there in 2016. The latest poll, conducted partly after Biden’s huge win in South Carolina but before his shocking rampage on Super Tuesday, looks different:

That poll is deceptive in that it implies a close-ish race when there’s reason to believe the race isn’t all that close. If two-thirds of Warren’s voters there break for Bernie, that would net Sanders 2.3 points — nice, but not enough to overtake Biden. Meanwhile, Joe’s likely to pick up the overwhelming majority of Bloomberg’s 10.5 percent, which will not only offset those Warren votes for Bernie but push him up to a double-digit lead. And nearly a third of the entire electorate is undecided here, probably because they’re generally on the fence or were leaning towards Buttigieg or Klobuchar a few days ago. I’ll give you one guess which way the bulk of those undecideds are apt to tilt, especially with Pete and Amy having now endorsed Biden.

He could win by 20 points or more here, in other words, in what’s supposed to be a Bernie state. There are other promising omens for him in Michigan based on the demographics and exit polling from Super Tuesday:

Sanders wound up beating Clinton 50 percent to 48 percent on primary day — and he did it in part by running 15 points ahead of her among whites without a college degree, who made up a larger share of the electorate (36 percent) than any other group…

But the problem for Sanders is that Biden isn’t Hillary Clinton — and momentum tends to outweigh historical analogies. On Super Tuesday, Biden won non-college-educated white voters in eight states, according to the exit polls; Sanders won them in four. Crucially, Biden swept blue-collar whites in the two northern states most like Michigan: Minnesota (where Biden won non-college whites by 12 points) and Massachusetts (where Biden won them by 8 points). That was a key reason why Biden upset Sanders in both primaries, which Sanders was widely expected to win.

Bernie’s secret ingredient in 2016 is one of Biden’s secret ingredients in 2020. There are 125 pledged delegates at stake in Michigan; there are 219 at stake the following week in Florida. As noted this morning, Biden’s going to blow the roof off in the latter and might well win going away in the former. If he does, adding to an already probably insurmountable national delegate lead and proving that he’s more viable in two key swing states than Sanders is, what’s left of this race realistically?

In hindsight, Hillary’s weakness against Bernie in the 2016 Michigan primary was a harbinger that she was vulnerable against Trump in the Rust Belt in the general election. If Bernie loses this time by 25 or whatever, Team Joe will torture him with the talking point that he’s the weak link as nominee in the midwest this time. Look again at the detail in the Reuters post up top about the massive shift in perceived electability between the two since Biden’s big win in South Carolina. My theory of the nuclear Joementum we’re seeing is that lots of Democrats nationally wanted to support Biden, chiefly on electability grounds, but were holding their breath after he faceplanted in Iowa, New Hampshire, and Nevada. South Carolina was the acid test: Mr. Electability had to win there, big, and prove that he was worth gambling on. He did, which led Democrats to exhale. Now that Joe’s reestablished himself as the electable candidate in the race and is poised to demonstrate that in gory ways in Michigan and Florida, what can Bernie do? What’s the argument for continuing this exercise in futility if, realistically, he can’t catch up to Biden in delegates?

There isn’t even a debate this weekend to give Biden a chance to embarrass himself. Six states, including Michigan, will vote before Joe takes the stage again on the 15th. And his lead in Florida is so enormous at this point that it’s probably gaffe-proof. He’s likely to have a prohibitive delegate lead soon no matter what Sanders does.

And there may be one man above all others whom Biden has to thank for that. No, not Barack Obama.

You know who paved Biden's path to the nomination? Donald Trump, by accelerating the migration of upscale suburban GOP moderates into the Dem primary electorate.

— Dave Wasserman (@Redistrict) March 5, 2020

The suburbanites who delivered the House to Democrats in 2018 also helped deliver a world-beating surge for Biden two days ago. If he’s the nominee, there’s every reason to believe right now that they’ll hang with Team Blue this fall.

Here’s Bernie telling Rachel Maddow last night that if Biden has more “votes” than him at the convention, then yes, he should be the nominee. (By “votes,” I think he means delegate votes, not national popular votes. Although Biden will almost certainly lead in that metric too.) As I say, it’ll become clear soon that Biden will in fact have more delegates in Milwaukee than Bernie no matter what happens over the next three months, which means Bernie will come under heavy pressure to accept reality and bow out. And maybe not just from centrists; there may be progressives too who are willing to admit he’s beaten and that it can only hurt the anti-Trump effort to keep this going. Exit question via NBC: Would it be better for lefties if Warren endorsed Biden? “Privately, some Warren allies say she might be able to exert more influence over Biden’s campaign and potential administration than Sanders since her support could be more valuable to a moderate candidate.” If backing Sanders won’t change the outcome, she might as well start earning favors for progressives from Joe.