ANN ARBOR, Mich. ― If Bernie Sanders doesn’t win the Michigan primary on Tuesday, it won’t be for lack of trying.

Starting on Friday night, the Vermont senator and Democratic presidential candidate held seven events in the state over the course of 72 hours. The itinerary included town hall events in Dearborn and Flint, as well as large rallies in Ann Arbor, Detroit and Grand Rapids.

The Sanders Michigan tour featured some progressive star power, too, with the Rev. Jesse Jackson appearing in Grand Rapids to offer his official endorsement and Rep. Alexandria Ocasio-Cortez (D-N.Y.) introducing Sanders to the throngs in Ann Arbor.

Joe Biden, the former vice president and front-runner for the nomination, has relied heavily on paid advertising, spending $820,460 in Michigan, according to data collected by Kantar Media/CMAG. That’s just shy of the $892,090 Sanders spent.

And Biden finally came to Michigan on Monday with a blitz that also stopped in Flint before winding up a Detroit. He brought along some guests, too: Sens. Cory Booker (D-N.J.) and Kamala Harris (D-Calif.), each of whom had just endorsed him.

But over the weekend, Sanders had the local airwaves mostly to himself, in part because he also did multiple interviews with local news correspondents. He even did a round of segments, by satellite, with anchors from the northern part of the state and Upper Peninsula ― an area that almost never gets attention from national politicians.

The rallies, meanwhile, meant Sanders got to make contact with and energize a small army of grassroots supporters. Officially nearly 30,000 people in total turned out to see Sanders in Michigan in those three days, and even if some of those counts felt a little inflated, they dwarfed the crowds for Biden, whose largest audience fit inside a high school gymnasium.

If we are going to defeat Trump, in Michigan ... it will be very hard for a candidate who voted for these disastrous trade agreements. Sen. Bernie Sanders at a rally in Detroit

The attention Sanders is giving Michigan is a sign of just how much he is counting on the state to revive his electoral fortunes, just like it did four years ago, in 2016, when he narrowly defeated former Secretary of State Hillary Clinton. Although Sanders went on to lose the Democratic presidential nomination, the victory in Michigan gave him enough standing to stay in the race until the end.

The parallels are impossible to miss.

Then, as now, Sanders came into Michigan following significant losses across the country on Super Tuesday. Then, as now, Sanders stood to lose in other races on the same day as Michigan, especially in the South.

And then, as now, Sanders beat Clinton in part by spending a lot more time here. It was a preview of what would happen in the fall, when Clinton lost Michigan, along with the rest of the Upper Midwest and, in the process relinquished the presidency to Donald Trump.

But at least two key factors are different this time around. Both almost certainly work in Biden’s favor. That could make it difficult for Sanders to repeat his feat from four years ago and, especially if he loses by a substantial margin, put his 2020 bid in serious trouble.

This Time Sanders Isn’t Running Against Clinton

One difference is that Sanders is not running against Clinton, whose favorability rating among Democrats and Democratic-leaning voters nationally had fallen behind Sanders’s when Michigan voted in 2016. This time, Biden is the one with the higher favorability rating, according to the latest Quinnipiac poll.

In 2016, Sanders, with his record of opposing free trade agreements and attacking Wall Street, had an easy time presenting himself as an alternative who was on the side of average Americans.

Over the weekend, Sanders did his best to draw the same kinds of distinctions with Biden by attacking the former vice president for his past support of the same trade agreements that Clinton had backed ― and for running on the support of the same political establishment, including its wealthy funders.

“Joe Biden and I have a very different record on an issue of great importance to the people of Michigan, the Midwest and, in fact, the whole country,” Sanders said at a Friday rally. “I helped lead the opposition to NAFTA [the North American Free Trade Agreement] and PNTR [permanent normal trade relations] with China, which has cost us over 4 million good-paying jobs in this country.”

Sanders is right about Biden’s record, and it’s not a stretch to think, as Sanders said, that, “if we are going to defeat Trump, in Michigan, in Pennsylvania and in Wisconsin, it will be very hard for a candidate who voted for these disastrous trade agreements.”

I'm not worried he'll go all wishy-washy. Lori Goldman, president of Fems for Dems, on Joe Biden's support for reproductive rights

But Biden also has a reservoir of goodwill with white working-class voters, which is one reason he performed so well on Super Tuesday. And though it’s impossible to know exactly why, it likely reflects a combination of factors ― including his longtime ties to major union leaders as well as his image as somebody who is both from and protective of the working class.

Sanders in Michigan also did his best to win over female voters by emphasizing his staunch defense of reproductive rights and contrasting it to Biden’s record.

As Sanders made sure to note at every stop and in his interviews with local TV, Biden once criticized Roe v. Wade, the Supreme Court case that guaranteed a right to abortion, and supported the Hyde Amendment, which prohibits federal funding of abortion through programs like Medicaid, until changing his position on it just last year.

But though every word of what Sanders said was true, polling around the country suggests women in the Democratic Party prefer Biden anyway. That’s especially true of the suburban women who in 2018 helped Democrats win back the U.S. House and sweep statewide races in Michigan.

Lori Goldman, founder of an organization called Fems for Dems based in Detroit’s Oakland County suburbs, says she isn’t surprised.

Yes, the women there feel strongly about reproductive rights, she says, but they believe Biden will be there for them, in part because he’s responsive to the party and that’s where the party is.

“I’m not worried he’ll go all wishy-washy,” she told HuffPost.

This Time Trump Is President

The other difference from 2016 is that, back then, the prospect of a Trump presidency was purely hypothetical ― and a far-fetched one at that. If people were restive and wanted change, that meant change from President Barack Obama’s administration, in which Clinton had served and which Sanders had frequently attacked.

Now Trump is president and Democrats, whatever their ideological leanings, are desperate to get him out.

Sanders over the weekend made the case for why he’s actually the most electable ― because, he said, he has the ideas and the movement to increase turnout.

“I understand that Joe Biden has the support of the political establishment,” Sanders said in Ann Arbor. “But we have the support of some of the strongest grassroots movements in this country. … and I would, 100 times over, prefer to have grassroots support over establishment support.”

His supporters echo those arguments, just as they echo Sanders’s arguments that policies like “Medicare for All” and free college are more popular than critics allow. They also talk about him as somebody who speaks his mind and comes off as genuine ― and how that credibility can go a long way in an election.

“I’ve been following Bernie for at least a decade,” Jeremy Manning, a network administrator from a Detroit suburb, said on Friday night. “He’s honest and consistent, and I think people get that.”

But on Super Tuesday, it was Biden supporters whose turnout exceeded predictions. And one reason may be that many Democratic voters still harbor doubts about whether Sanders, with his agenda for unprecedented government expansion and identity as a democratic socialist, can win.

Among those harboring the biggest doubts are African Americans, whom Sanders has struggled to attract.

Brittany Greeson via Getty Images More than 10,000 came out to see Sen. Bernie Sanders at the University of Michigan in Ann Arbor, according to official estimates.

“This doesn’t look like Detroit ― this looks like Ann Arbor,” Angela Gilchrist, a local public school teacher, quipped after surveying the conspicuously white crowd on Friday night. Gilchrist says she is a strong Sanders supporter but as a Black woman she can understand why so many other Black voters prefer Biden. “There’s just this practical side of things. People think about electability. I get it.”

None of which is to say Sanders can’t defy the odds, like he did last time. Turning out tens of thousands of people to rallies may not be everything in politics, but it’s not nothing, either. It’s always possible the pollsters have underestimated the youth vote. Sanders is expected to beat Biden handily among young voters, as he did against Clinton in 2016.

In his tour of Michigan over the weekend, Sanders also zeroed in on some key issues, like the future of the state’s water supply, that traditionally figures big in state politics. In addition, Sanders can count on strong support from Detroit’s Arab American community, which is among the largest Arab communities outside of the Middle East.

Sanders has campaigned there repeatedly, going back to 2016, and with so many residents fearful of or hostile to Trump, Sanders may have more appeal than ever.

“The Arab American community is overwhelmingly supporting him,” Sam Baydoun, a Wayne County commissioner and Sanders supporter, said after the Dearborn event. “This district is full of immigrants. ... He talked about an even-handed approach to the Israeli-Palestinian conflict. That’s very important.”

Once Again, Michigan Could Be Pivotal

Democratic Rep. Debbie Dingell was there, too, though she made it clear she was neutral and attending simply because the event was in her district. Ann Arbor is also part of that district, and Dingell told reporters she thought Sanders would carry it, just as he did in 2016, although she predicted he’d “have to work hard to get the victory” in the rest of the state.

Sanders seemed to be operating under the same premise. At every stop over the weekend, he reminded voters of how much was at stake ― and how much he was counting on them to do what the pollsters say they won’t: Turn out the vote enough to give him a victory.

He’s honest and consistent, and I think people get that. Jeremy Manning, Detroit-area voter, on why Sanders can win over wary voters

“Tuesday is a very very important day, and Michigan is the most important state coming up on Tuesday,” he said in Ann Arbor. “We need you to come out, or to vote early. We need you to bring out your families and your co-workers.

If it works, if those enthusiastic hordes carry Sanders to another upset, they will do more than keep him close in delegates. They will offer some much-needed proof of his political hypothesis: that, whatever his liabilities as a candidate, he can generate enough support among young people, traditionally marginalized groups and disaffected white working-class voters to win.

But the opposite is also true. If the Sanders wave does not materialize, if Michigan’s results look like all those Super Tuesday losses, his political hypothesis will seem a lot less plausible, and so will his prospects of winning the nomination.