Ever since former Vice President Joe Biden’s fast and decisive campaign resurrection, the momentum has been on his side.

He dominated in the South on Super Tuesday and stole victories in states like Maine and Massachusetts that once were trending towards Sen. Bernie Sanders (I-VT). He even staunched the bleeding in California, finishing well above the viability watermark and mitigating the damage Sanders was formerly poised to inflict there.

The March 10 primaries could be Sanders’ last, best shot to slow the Biden juggernaut before delegate math — and demographic reality — create too steep an uphill climb to surmount.

As we saw from Biden’s 180, things can change. If Sanders gets some wind back, he could change his fate in the closely contested states, and maybe limit the damage Biden will do in his strongholds. But for there to be a chance of that, Sanders has to turn that corner tonight.

Michigan

125 delegates; polls close at 9 p.m. E.T. (though all but four close at 8 p.m. E.T.)

Michigan was once Sanders’ salvation.

In 2016, polls showing Hillary Clinton up 21 points failed to capture other dynamics in the race. Voters went to the polls and left Sanders with a 1.5 point upset and a bevy of positive headlines about his momentum.

This year, Sanders would have to pull off another spectacular showing. As of Monday, the FiveThirtyEight average gave Biden a 28.8 point lead following a series of recent polls.

“I really think Sanders needs to pull the rabbit out of the hat again in Michigan,” Kyle Kondik, managing editor of Sabato’s Crystal Ball, the newsletter from the University of Virginia’s Center for Politics, told TPM. “He needs some big, surprising outcome to resuscitate his campaign, and Michigan is the only state that can deliver that on the slate tomorrow.”

Michigan is Tuesday’s biggest prize, yielding 125 delegates. As such, whoever wins will likely shape the narrative afterwards, despite the fact that any kind of close finish will not hugely alter the delegate math. Polls close in all but four counties at 8 p.m. ET, so coverage of the Wolverine State will likely dominate the night of results.

Michigan State associate professor of political science Matt Grossmann rates a Sanders miracle as unlikely, pointing specifically to this year’s lack of a contested Republican primary. Michiganders can vote in either primary — Grossmann posits that in 2016 some would-be Hillary Clinton voters may have skipped the Democratic primary, dismissing it as a foregone conclusion, in favor of the Republican primary where Donald Trump was surprisingly competitive. That ultimately may have allowed Sanders an under-the-radar victory, Grossman said.

Aside from that factor, Lansing-based political consultant Mark Grebner thinks that Sanders just lacks the foundational support needed to win the state this time around.

“One point three million, 1.4 million people will vote in this Democratic primary and a million of those are the most usual suspects you’ve ever seen in your life: 50, 60, 70 year old, well-established Democratic voters,” he said. “The stampede you heard is that crowd all running to Joe Biden.”

Washington

89 delegates; polls close at 11 p.m. E.T.

The race for Washington’s delegates is neck and neck, with Biden currently leading by less than a point.

Sanders won the state big in 2016, netting 72.4 percent of the vote.

But since then, Democrats have ditched the caucus system to allocate delegates based on a primary.

As Washington pollster Stuart Elway told TPM, that change will probably hurt Sanders.

“You have to be real committed to go to those and sit there for the hours it takes, and Sanders’ core constituency has that kind of dedication,” he said of the caucuses.

In 2016, Washington held a just-for-kicks (not for delegates) primary after the caucus — and Clinton won by 5 points.

“In the caucuses, maybe at most a couple hundred people participated four years ago,” Elway said. “One point four million voted in the primary. The caucuses don’t necessarily represent the broader constituency in either party because of the dedication it takes to go and do that.” He called this year’s race a “true toss-up,” though he thinks the momentum is with Biden.

Another possible curveball in the race is the coronavirus, which has struck Washington state with particular venom. As of Monday, there are 142 confirmed cases and have been 19 deaths.

The state operates with mail-in ballots, so disruptions may be more limited than they would be otherwise. The Washington Secretary of State did not immediately respond to queries about any expected ballot tallying delays due to precautions surrounding the disease, but Washington voters are being advised not to lick close the envelopes containing their ballots.

As recommended by @WADeptHealth, please use alternative methods to seal your ballot return envelopes, such as a wet sponge or cloth. Washington’s Presidential Primary is March 10. Use a ballot drop box to return your ballot by 8 p.m. Election Day. #waelex pic.twitter.com/UOk8Ld4Z3m — WA Secretary of State (@secstatewa) March 3, 2020

Missouri

68 delegates; polls close at 8 p.m. E.T.

A Monmouth University poll published Monday shows Biden with a 15-point lead over Sanders in Missouri.

If Biden did take the state in such a commanding manner, it would be a drastic departure from 2016 when Clinton won the state by .2 percent of the vote.

Dave Roberts, chair of the political science department at the University of Missouri-St. Louis, said that Biden is trending stronger than Clinton did in some critical working class enclaves, like Jefferson County, south of St. Louis.

“This time it seems like it will drift back to Biden, after it went Sanders in 2016,” he told TPM. “It’s part of the working class rejection of Sanders you’re seeing in Michigan and some other places.” He added that there was a significant anti-Clinton vote last time that Biden doesn’t seem to be contending with.

Roberts also noted the small percentage of Latino voters in the state — who Sanders has done well with this year — compared to the “great strength” of African Americans, who make up about 12 percent of the population, helped boost Clinton to her win in 2016 and who have favored Biden this time.

Political science professor Peverill Squire of the University of Missouri agreed that the state was “apt to tilt in Biden’s direction” with or without the South Carolina/Super Tuesday surge.

“He is able to connect with working class and middle class Missourians in a way that Hillary Clinton could not,” Squire told TPM. “Biden does not come off as elitist, and at a time of seemingly endless crises and conflict, I suspect many Missouri Democrats are comfortable with him as the party’s likely nominee.”

Mississippi

36 delegates; polls close at 8 p.m. E.T.

The Magnolia State, safe in Biden’s southern stronghold, looks good for the former Vice President. There haven’t been many polls of the state, but one from Data for Progress published Sunday had Biden up 55 points.

Even without Biden’s momentum, the demographics in the state simply suit him much better than they do Sanders.

“Seventy-five percent of the electorate on Tuesday is going to be African American,” said Brad Chism, president of a Jackson-based political communications firm. “I fully expect a healthy Biden win.”

Idaho

20 delegates; polls close at 11 p.m. E.T.

Idaho is another state that is ditching its caucus system for a primary this year.

In 2016, Sanders crushed Clinton with almost 80 percent of the vote. It’s hard to see Sanders netting such a huge majority in a primary, but there is next to no data from the state.

“Sanders is, as I understand it, somewhat favored,” said Markie McBrayer, assistant professor of political science at University of Idaho. “We don’t have any polls, so we can’t really know too much at this point.”

North Dakota

14 delegates; polls close at 8 p.m. E.T.

In a familiar tune, North Dakota has also switched out its caucus, but for something called a “firehouse caucus” — which, despite its name, is essentially a state-party run primary.

The state is also introducing mail-in ballots this year.

Sanders won in 2016 handily: 64.2 percent to 25.6 percent. The new format will likely hurt Sanders, but it’s not yet clear by how much.