Sanders also beat Biden handily with Latinos in Texas, nearly one-third of the vote, but Biden maintained his even bigger edge with black Americans and drew about evenly with Sanders among whites. Meanwhile, Sanders showed no particular strength in the state’s sprawling suburbs and watched Biden edge him out with women.

The age gap could be problematic in upcoming primaries that increasingly look like must-wins for Sanders. He needs to draw more older voters to his side, while also bringing out his younger supporters at even higher levels than before.

«Several of the big states in the Midwest coming up — Missouri, Michigan, Illinois, Ohio — they tend to be older states,» said William Frey, a demographer and senior fellow at the Brookings Institution. «The issue with Bernie’s coalition is they’re iffy with turnout.»

The demographic setbacks have been bruising for Sanders. His campaign has spent months trying to improve his standing with key groups, such as black Americans, mindful that those voters contributed to his loss to Hillary Clinton in 2016. But Sanders has seen only middling progress. In some states, he’s managed to give Biden a challenge with younger blacks, but not enough of those voters are casting ballots to make a difference.

Sanders’ solution to this coalition math problem has been to try to bring more of his voters to the game. But Tuesday’s elections in Virginia and North Carolina showed little evidence that’s happening. There were obvious signs of the sort of enthusiasm Sanders often discusses — new voters drawn to the process by a sense of urgency and a desire to change Washington. In Virginia, a full 500,000 more voters cast ballots Tuesday compared with the 2016 Democratic primary.

But the increased turnout isn’t helping Sanders. His vote share dropped from 35 per cent in 2016 to under 25 per cent — and his raw vote total rose by fewer than 50,000 votes. Biden alone earned about 200,000 more votes than Clinton did four years ago.

Enduring weaknesses

In North Carolina, Democratic turnout was up by 180,000 votes from 2016. Sanders walked away with 100,000 fewer votes in 2020.

Sanders’s base in these states — and across the country — has been remarkably consistent. In addition to young people and Latinos, Sanders garnered support from people who felt left behind financially. He tends to pull in support from men, people without college degrees and liberals.

In some places, this coalition has been able to yield a victory. He banked victories in Nevada, Colorado and was leading in California, all states with sizable Latino populations. In California, where about 30 per cent of Democratic primary voters were Latino, VoteCast showed about half of them went to Sanders. In Colorado, where 13 per cent of Democratic voters were Latino, he won a solid 42 per cent of their votes.

But Super Tuesday showed some enduring weaknesses with three other groups of Democratic voters: women, suburbanites and college graduates.

Women make up a decisive majority of Democrats and any potential nominee will likely need to win their vote. But Sanders has struggled to best his rivals with women. In Texas, women slightly favoured Biden over Sanders. In Virginia, Biden beat out Sanders among women by more than 2 to 1.

Nor does Sanders have a steady foothold in the suburbs, where the bulk of likely voters in November happen to live. He fared reasonably well in the suburbs of California, Colorado and Texas. But his support was minimal in most other states. He won just 27 per cent of suburbanites in Minnesota, compared with 41 per cent who went for Biden.

He has also faced difficulty in attracting college graduates, a group that is increasingly drawn to the Democratic Party during Donald Trump’s presidency. This vulnerability was clear by the crushing defeat in Virginia. College graduates made up more than half of that state’s primary voters. He only managed to win 21 per cent of them. About half went with Biden.