The fight for the Democratic presidential nomination is now a two-man race. On Tuesday, former Vice President Joe Biden and Sen. Bernie Sanders won nearly all the delegates at stake in 15 states and territories. On Wednesday, former New York Mayor Michael Bloomberg dropped out. Sen. Elizabeth Warren, far behind in the delegate count, is conferring with advisers to “assess the path forward.” It’s been a crazy week, so nothing is certain, but Biden has the upper hand. He didn’t just win most of Tuesday’s primaries and pull ahead in the delegate count. He also has three underlying factors working in his favor, as revealed in returns and exit polls.

First, Super Tuesday wasn’t a single day of voting. It was decided in two stages. Many candidates who have since dropped out competed in the first stage, in which a lot of voters made up their minds—and in many cases submitted early ballots—months or weeks ago. Then, after South Carolina voted on Saturday, there was a second stage: The race narrowed to Biden, Sanders, Warren, and Bloomberg, and the remaining voters chose among those candidates. Sanders did well in the first stage, but Biden crushed him in the second. And because the second stage more closely resembles the field that remains, it’s a warning of what’s ahead.

Sanders won four of the 15 primaries: California, Colorado, Utah, and his home state of Vermont. But in every state where voters were asked when they had decided on a candidate—including the states Sanders won—Biden beat him among people who made up their minds in the last few days. In several states, late-deciding voters represented about half the electorate. In this second-stage race, Biden beat Sanders by 34 percentage points in Minnesota, 30 in Maine, 29 in Texas, and 23 in Massachusetts. It was a blowout.

Late deciders, by definition, are less likely to be committed to a candidate and more likely to be influenced by momentum and electability. But on a day when a dozen primaries were exit-polled, you’d expect Sanders to win late deciders in at least one state. Even in Vermont, he narrowly lost them, 35 percent to 32 percent. And that’s the only place where he came within single digits of Biden.

There’s no guarantee that Bloomberg’s voters will move to Biden. But the most recent data on this question imply that most of them will.

Second, in all but two the 15 primaries, the combined vote for Biden and Bloomberg—who had positioned himself as the anti-socialist in the Democratic field—was bigger than the vote for Sanders. That means Biden has an extra reservoir of votes he can exploit in the contests ahead. In California’s incomplete returns, Biden and Bloomberg collectively outpolled Sanders by 5 percentage points. In Colorado, they outpolled him by 8 points. In Utah, they were almost dead even. Only in Vermont did Sanders hold a clear lead.

There’s no guarantee that Bloomberg’s voters will move to Biden. But the most recent data on this question, released by SurveyUSA, imply that most of them will. When Bloomberg’s voters were asked to name their second choice, 44 percent picked Biden. Another 19 percent picked Pete Buttigieg or Amy Klobuchar, who have since endorsed Biden. Only 25 percent picked Sanders. And that was before Bloomberg, on Wednesday, urged his supporters to switch to Biden.

Some pundits on the left think that if Warren were to drop out, her supporters would move to Sanders. But polls suggest that in reality, the result would be a wash. In the SurveyUSA sample, 45 percent of Warren’s supporters picked Sanders as their second choice. Another 45 percent picked Biden, Buttigieg, Klobuchar, or Bloomberg. The subsample for these calculations was small, but the results match findings from other surveys. If Warren’s voters split evenly between Sanders and Biden, while Bloomberg’s voters break toward Biden, Sanders is in trouble.

Third, Tuesday’s exit polls indicate that Biden is closer than Sanders, ideologically, to the center of the Democratic primary electorate. I’m not talking here about “centrism” or the party leadership. I’m talking about everyone who’s participating in Democratic primaries, including the new voters Sanders has attracted.

In Iowa and New Hampshire, the numbers were ambiguous. By some measures, most people who participated in those Democratic contests were liberal; by other measures, they were moderate. But in the Super Tuesday exit polls, one question elegantly captured the difference between Biden and Sanders. It asked whether the next president should “return to Barack Obama’s policies,” “change to more liberal policies,” or “change to more conservative policies.” Biden has positioned himself as the Obama candidate. Sanders has positioned himself as the champion of a more progressive agenda.

In Vermont, 51 percent of voters chose “more liberal policies.” But in the other 11 states where this question was asked, the “more liberal policies” camp was outnumbered by voters who preferred Obama’s policies or more conservative policies. In California, Minnesota, and Massachusetts, most voters favored Obama’s policies or a more conservative agenda. In Virginia, North Carolina, Texas, Tennessee, Oklahoma, and Alabama, the majority for Obama’s policies or for more conservative policies was overwhelming.

In every state, Sanders won the bloc of voters who wanted more liberal policies, but Biden won the other two blocs. When you combine that advantage with the additional pro-Obama or more conservative voters who went for Bloomberg, Buttigieg, or Klobuchar, Biden’s leverage looks even stronger. It’s no wonder that at every rally in the past week, he has praised Obama and called himself an “Obama-Biden Democrat.”

Not everything in the exit polls looks bad for Sanders. Socialism polled fairly well in the five states where it was tested. Pluralities favored it in Tennessee and North Carolina, and majorities favored it in California, Texas, and Maine. In 11 states, majorities supported “replacing all private health insurance with a single government plan for everyone.” In the other state where that question was asked, Massachusetts, a plurality supported it. But Biden’s alternative, a public option, wasn’t tested in these polls, so it’s hard to know how that fight would shake out. It’s worth noting that Sanders, while raising other differences with Biden at recent rallies, has chosen not to raise this one.

Sanders is close in the delegate count. He has lots of money, an enthusiastic base, and high favorability ratings. Only Biden still stands in his way, and Biden has had trouble speaking coherently and exciting people. But the underlying composition of the Democratic electorate favors the former vice president. It’s his race to lose.