When Sen. Bernie Sanders talks about his presidential campaign, he emphasizes that it’s a movement — the start of a “political revolution,” which he says will drive typically apathetic voters, particularly the young, to turn out and vote.

But if Super Tuesday was anything to go by, Sanders’s political revolution isn’t happening — and it’s former Vice President Joe Biden’s campaign, or perhaps general opposition to President Donald Trump, that seems to be driving turnout.

Consider Texas: According to NBC News’s exit polls, the Democratic electorate actually skewed older in Tuesday’s primary compared to past primaries. In 2008 and 2016, 13 and 18 percent of the electorate, respectively, was 65 and older. In 2020, it was 24 percent.

Texas is getting older, but not at a rapid enough rate for that increase to be tied solely to state demographic trends. In fact, the share of the population that’s 65 and older is just 12.6 percent. Given Biden’s strength with this group of Texas voters — 46 percent support Biden, while just 16 percent support Sanders — that surge in older voters helps explain Biden’s narrow victory in the state.

It seems like Texas wasn’t an outlier. Domenico Montanaro at NPR found that, from the start of the primary elections to Super Tuesday, we just haven’t seen a surge in younger voters:

Before Tuesday, voters younger than 30 were not keeping pace with the overall increase in voter turnout. In fact, young voters’ share of the electorate went down in three of the first four states compared with 2016. On Tuesday night, not a single state saw an increase in young voters’ share of the electorate, according to exit polls conducted by Edison Research and sponsored by several of the television networks.

It’s really hard to overstate how bad this is for Sanders. It’s not just that his campaign relies on these voters, although it does. It’s that a core driving philosophy of his campaign is that he will inspire a political revolution, one led, in particular, by a surge in young voters. That’s how he has envisioned defeating Trump in November. If that’s not happening, then how is the Sanders campaign a movement at all?

Political analyst Dave Wasserman put it in blunt terms on Tuesday: “Sanders’s pledge to bring new voters into his movement seems fairly empty in the results we’re seeing so far. His coalition has shrunk since 2016, not grown.”

That’s not to say it’s all bad. On Tuesday, Sanders did win in Vermont, Colorado, and Utah, and, as of Wednesday morning, he has a significant lead in California. He has made inroads with Latin voters, who fondly call Sanders “Tío Bernie.”

But just winning a few states isn’t enough here. Sanders has promised that his campaign would bring all sorts of new voters into the Democratic Party. And so far it seems to be struggling to do so.