With the Democratic primaries down to two real candidates, only one state really mattered on mini-Super Tuesday: Michigan. Bernie Sanders has staked his electability on his alleged unique ability to win swing states like Michigan, the so-called “rust belt” states that had fallen to Donald Trump in 2016. In fact, some of the most questionable decisions of his 2020 campaign – doing a Fox News Town Hall and touting a controversial endorsement by Joe Rogan – were based on the rationale that Sanders alone could win back white working-class voters who had abandoned the Democratic party for Trump.

Despite trailing in the polls by 25%, he had eked out a narrow but significant win over Hillary Clinton in the 2016 primaries. Sanders supporters hoped this would play out again on Tuesday night, but it was not to be. His loss to Joe Biden might not shake the belief of Sanders and his supporters that he, and he alone, can defeat Trump in November, but it most likely does end his chance at winning the Democratic nomination.

This should not really have come as a surprise. Despite all the hype after the first three primaries, in wildly unrepresentative and largely irrelevant states, Sanders was winning by pluralities between one-quarter and one-third of the vote. In several cases his support was only half that of 2016, suggesting his surprise success last time was as much anti-Clinton protest as pro-Sanders support. Even when the field started to thin, Sanders only won a majority in his home state of Vermont, and only barely so.

While Super Tuesday was brutal for the large size of the Biden wins, the modest Sanders wins were equally telling. Despite massive campaigning efforts in terms of both money and personnel and very favorable poll numbers for weeks, Sanders won just 34% of the vote in California. Biden, who had barely campaigned in the Golden State, came second with 27%, just seven points behind.

After the disappointment of Super Tuesday, Sanders’ campaign had prioritized Michigan, pulling out of Mississippi, doubling his organizational staff in the Great Lake state, spending millions on increasingly negative ads against Biden, and holding rallies with his most popular surrogates, including Alexandria Ocasio-Cortez, Cornel West, and Michael Moore. In sharp contrast, Biden visited Michigan just once, in a rally where Cory Booker and Kamala Harris endorsed him, but he did use part of his new cash to narrowly outspend Sanders.

This time Sanders was not saved by “an unexpected surge of younger voters”, or by his “firewall” of blue-collar voters. While Sanders did poll ahead of Biden among the young and among white Americans without a college education, they were not enough to offset Biden’s advantage among older, moderate and suburban white voters as well as older African American voters.

And this is pretty much the story of the Democratic primaries, at least since Super Tuesday. To put it sarcastically: young people tweet, old people vote. According to analyses of exit polls in 12 key states by the Harvard pollster John Della Volpe, the youth vote (under 30) only increased in a minority of the contests. In sharp contrast, turnout among those over 30 has been up in virtually every state, with some huge increases among the oldest cohort (over 65) – including in (potential) swing states such as New Hampshire, North Carolina and Virginia.

So, where does that leave Sanders and the Democratic primary race? Until Super Tuesday Sanders ran largely as an Independent, a “democratic socialist” attacking “the Republican establishment” and “the Democratic establishment” with equal fervor. While this satisfied his core base, which has seemed much larger than it actually was because of its disproportionate activity, organization and size on social media, it did little for the broader Democratic electorate.

After Super Tuesday Sanders tried to “reset” his campaign, mostly by prioritizing the midwestern states, by reaching out more to African American voters, and by attacking Biden’s track record. He also doubled down with attacks on “the corporate media” and “the Democratic establishment”. The Michigan results show that this strategy has not worked either.

The argument that Sanders should get the nomination even if he wins only a plurality of delegates is becoming increasingly irrelevant. The claim that only Sanders can mobilize two key groups in November, independents and young voters – which has always lacked empirical evidence – is further weakened by the lower turnout of young voters in the primaries. At this rate, not only will Sanders fail to win a plurality of delegates – Biden could win a majority outright.

As Sanders’ chances at the presidency start to fade, perhaps the most important part of his campaign is about to start: convincing his staunchest supporters, the so-called “Bernie or Bust” crowd, to come out to vote for Biden in November. Because however big Biden’s victory will be in the Democratic primaries, he cannot defeat Trump without the vast majority of Sanders’ supporters.