Jeff Roberson / AP

Updated on March 11, 2020, at 1:31 p.m. ET

After two insurgent campaigns that rattled American politics, Bernie Sanders’s dream of becoming the Democratic presidential nominee is effectively over.

Tapping an enormous wave of grassroots energy in both bids for the White House, Sanders galvanized young people, transformed online fundraising, and changed the terms of debate in the Democratic Party on issues ranging from health care to college affordability. But as his defeats last night made clear yet again, his unflinching call for a “political revolution” could not build a coalition broad enough to capture the ultimate prize.

For now, Sanders is staying in the race. “While our campaign has won the ideological debate, we are losing the debate over electability,” he said today in a short speech from Burlington, Vermont. He still plans to attend an upcoming debate with former Vice President Joe Biden, who remains well short of the 1,991 delegates needed for a nomination on the first ballot at the Democratic National Convention in July. But Biden’s resounding victories last night, and his widening delegate lead, have prompted even some of Sanders’s ideological allies to question whether the senator from Vermont should continue his campaign.

“Sanders should start thinking through what outlet he has to draw concessions from Biden, and it’s not clear to me that continuing a presidential campaign that does not have a path to victory is one of those options,” says Sean McElwee, a co-founder and the executive director of the liberal research and advocacy group Data for Progress, which has been polling extensively in the primary states. “I think he should … think soberly about the reality. I don’t think there are any states right now he is favored to win.”

Others on the left did not go so far. The Progressive Change Campaign Committee, which had endorsed Senator Elizabeth Warren of Massachusetts before she withdrew, issued a statement last night urging Sanders to remain in the race at least through the debate, which will be held Sunday in Phoenix. Robert Reich, a leading liberal economic and policy analyst and a former labor secretary under Bill Clinton, said the same.

“People are going to be asking themselves as they watch that debate who is going to be better able to take on Trump one-on-one,” Reich said. “The stampede toward Biden was remarkably fast. That shows that his support is not absolutely steadfast, so it’s at least possible that if his debate performance is very bad on Sunday, Bernie Sanders could have a renaissance.”

But across much of the party, Biden’s triumphs in Michigan, Missouri, Mississippi, and Idaho confirmed the message sent by his victories on Super Tuesday: that the question is no longer whether, but when, the former vice president becomes the party’s nominee against Donald Trump.

As in last week’s contests, Biden last night dominated among African Americans; led among college-educated white voters; and even topped Sanders, albeit more narrowly, among blue-collar white voters, who had preferred the senator in each of the year’s first four contests. Compounding Sanders’s problem across the country, the young voters who generally preferred him by large margins over Biden consistently represented a smaller share of the total vote than they did four years ago, according to exit polls conducted by Edison Research for a consortium of media organizations.

“If he’s not going to win working-class [white voters], and he’s going to lose [black voters] massively, and the turnout is all with his opponent’s people and not his … there is just no path to victory,” says Tad Devine, who served as a senior strategist for Sanders in 2016 but is unaffiliated with any campaign this year. “It’s just that simple.”

Biden tried to project confidence in his victory speech last night, delivering conspicuously calm and measured remarks focused on the general election. And he offered the kind of conciliatory praise for Sanders that usually comes at the end of a primary race. “We share a common goal, and together we will defeat Donald Trump,” Biden said. “We will defeat him together.” Sanders, meanwhile, spoke volumes about his precarious situation by choosing not to speak until today.

While Democratic leaders more or less tolerated Sanders’s continuing his 2016 campaign against Hillary Clinton until June of that year, the party’s desire to beat Trump will likely make it much less forgiving of another extended crusade, Devine told me. “Biden needs the spring and the summer without Bernie,” he said. “I think Bernie is smart enough and reasonable enough to recognize that [it’s irrational] to keep this thing going for the sake of—what?”

One reason Sanders may want to stay in the race is to keep attention on the policy issues he cares about, even if he largely mutes his criticism of Biden. Jesse Jackson, who endorsed Sanders last weekend, followed that model in the latter stages of the 1988 Democratic primary, which Michael Dukakis ultimately won. In his comments today, Sanders said that “poll after poll, including exit polls, show that a strong majority of the American people support our progressive agenda,” pointing to concerns about income inequality and inadequate health care, among others.

Several Democratic operatives, though, say one major difference between 2020 and 1988 could complicate this approach: Sanders’s aggressive network of supporters is unlikely to muffle its criticism of Biden even if the candidate himself does. That could translate into escalating demands for Sanders to quit.

Beyond Democrats’ concerns about Trump, McElwee believes that Sanders will likely face more pressure to cede the field because of the coronavirus outbreak and the new constraints on campaigning. Such concerns prompted both Biden and Sanders to cancel events yesterday.

“Two things that are different about this year than 2016: One is … there are not going to be any races that he has any plausible shot at winning where he is going to be able to rebound,” McElwee told me. “And I think you had a little bit more mood among the electorate and establishment at large [in 2016] that said, ‘Let’s have a guy out there making a moral case.’ At this point … I think the Democratic base is much more terrified of Trump this cycle than last cycle and [is] going to respond less well to a long, drawn-out primary, particularly in the midst of a pandemic.”

The calendar doesn’t offer Sanders any reprieve. Next Tuesday, he must compete in Florida, where polls show him facing a cavernous deficit following his recent comments praising aspects of Fidel Castro’s rule in Cuba; Ohio, where he lost badly in 2016; and Illinois, where the state Democratic leadership has rallied around Biden and polls show the former vice president holding a hefty lead. Only Arizona, with its large Latino population, seems like it could be hospitable to Sanders, but even there the most recent survey found Biden comfortably ahead. Georgia, whose large black population establishes Biden as the clear favorite, follows a week later.

For Sanders, the losses last night were especially stinging because they came mostly in states where he ran well against Clinton four years ago. In that race, Sanders narrowly won the primary in Michigan; captured about two-thirds of the vote or more in Idaho, North Dakota, and Washington (where the elections were held as caucuses last time); and finished only 0.2 percentage points behind Clinton in Missouri. Only in Mississippi was he routed.

This time, though, Sanders continued to struggle to expand his support beyond the enthusiastic base that has filled his arena-size rallies and swelled his fundraising totals. Even at the outset of voting this year—when Sanders finished in a virtual tie for first place in Iowa and then won the subsequent contests in New Hampshire and Nevada—he attracted only between one-fourth and one-third of the total vote.

The big question for Sanders at that point was whether he could add to his coalition once the race consolidated, which it did with stunning speed when both former South Bend, Indiana, Mayor Pete Buttigieg and Senator Amy Klobuchar of Minnesota ended their candidacies and endorsed Biden just before Super Tuesday. Warren followed them off the field that Wednesday, after failing to win a single state the night before.

So far, Sanders, in key states, has failed to add to his base. On Super Tuesday, he exceeded 37 percent of the vote only in his home state of Vermont. In a two-person race last night, he drew only about 37 percent in Michigan, 35 percent in Missouri, about 33 percent in Washington, and an anemic 15 percent in Mississippi. Only in the smaller contests of Idaho (which he lost) and North Dakota (which he won) did Sanders cross 40 percent of the vote.

Demographic patterns largely followed the grooves cut on Super Tuesday. Biden ran up significant margins among college-educated white voters in Missouri and Mississippi, and carried them more narrowly in Michigan, a state where Sanders posted a double-digit advantage among them in 2016. Preliminary exit results also showed Biden winning those voters in Washington. Starting on Super Tuesday, Biden has won white-collar white voters in 13 of the 16 states in which exit polls have been conducted.

Biden last night also maintained his substantial advantage among African American voters. He won the support of nearly nine in 10 of them in Mississippi. As in 2016, Sanders has run more competitively among black voters outside the South. But even so, the exit polls last night found Biden winning about two-thirds of them in Missouri and Michigan, almost exactly matching Clinton’s performance last time. Biden has carried African Americans in every state with enough of these voters to measure in an exit poll.

Perhaps most disappointing for Sanders, the exit polls in Missouri and Michigan found Biden also narrowly winning the support of white voters without a college degree. (Not enough of them voted in Mississippi for the exit poll to record their preferences.) The preliminary exit results also showed Biden winning them by a slim margin in Washington.

Sanders carried non-college-educated white voters in Missouri and Michigan last time (no 2016 exit poll was conducted in Washington), and he targeted them this year by lashing Biden over his support for free-trade agreements and his earlier openness to cutting Social Security as part of a “grand bargain” with Republicans to reduce the deficit. Since Super Tuesday, Biden has carried blue-collar white voters in 12 of the 16 states in which exit polls were conducted (assuming his lead in Washington survives the final exit-poll revisions).

The sweep of Biden’s victory last night was best captured in the Detroit metro area. He beat Sanders by about 20 percentage points both in Wayne County, which includes heavily African American Detroit, and Oakland County, a white-collar suburb that has moved toward the Democrats in recent years. He also beat Sanders by about 17 points in Macomb County, the home of white, blue-collar “Reagan Democrats” who have drifted toward the GOP.

One final headwind battered Sanders. In a repeat of Super Tuesday, Biden dominated among voters who self-identified as Democrats in Missouri, Michigan, and Mississippi alike, and he carried them more narrowly in Washington.

After losing partisan Democrats badly in his 2016 run, Sanders had performed more competitively among them in the first contests this year. But at his moment of greatest triumph this cycle, after winning New Hampshire and Nevada, he sent a series of belligerent signals to the party. Among them: insisting he is running against “the Democratic establishment,” renouncing any general-election help from the billionaire Michael Bloomberg, and declaring that he would only pick a vice president who supports Medicare for All.

These factors likely contributed to Biden’s winning streak: He’s now won self-identified Democrats in every state with an exit poll since Super Tuesday, save for Vermont, California, and Colorado.

“The other flawed theory of this [Sanders] campaign is that you can win the nomination of a major political party by running against that political party,” Adrian Hemond, a Democratic consultant in Michigan, told me. “Democratic activists have invested the last 25, 30, 40 years of their lives in the party, and he was saying this was all bullshit. How’s that supposed to work?’”

On Tuesday, at least, the answer was that it didn’t work. Now, at 78, with his second campaign facing a lower ceiling of support than his first, Sanders and his leagues of ardent supporters are confronting the near-certainty that after years of organizing and struggle, he will never conquer the Democratic Party as its presidential nominee.

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