Bernie Sanders speaks at a rally in New Jersey in 2016.Dennis Van Tine / AP

Bernie Sanders’s entry into the 2020 race amounts to a big stone in a lake: It will generate ripples that touch every other candidate. But his own path to the nomination remains rocky unless he can attract a broader coalition than he did in 2016.

Whether or not Sanders claims the nomination himself, his bid could have a big impact on which candidate eventually does. Sanders will hurt contenders whose support overlaps with his, reducing the pool of voters available for those who are targeting the same groups most drawn to him, particularly young people, the most liberal activists, and independents who participate in Democratic primaries. That dynamic would most obviously affect Senator Elizabeth Warren of Massachusetts, but could also potentially weaken former Representative Beto O’Rourke of Texas, who’s mulling a bid. Yet it could simultaneously benefit the candidates with the least demographic and ideological convergence, a list that ranges from African American Senators Kamala Harris and Cory Booker to such relative centrists as Senator Amy Klobuchar of Minnesota and former Vice President Joe Biden, if he joins the field.

Sanders’s entry could also influence his competitors’ assessment of the earliest primary states, by causing other candidates to view the New Hampshire contest as a regional showdown between him and Warren. The state has a long history of favoring local contenders. “I can imagine candidates saying to themselves, Let the New England candidates fight it out over New Hampshire,” says Dante Scala, a University of New Hampshire political scientist and the author of Stormy Weather, a history of the New Hampshire primary.

That could muffle the contest’s impact: Though Scala, like many strategists already working on the race, considers it highly likely that New Hampshire will settle the competition between Sanders and Warren, if other candidates, the media, and voters in subsequent states downplay the New Hampshire results, that would dilute the state’s traditional role in winnowing the field. And that would increase the odds that three or more candidates could remain viable well into the primary process—a dynamic Democrats have not experienced since the 1980s.

But for all his influence, Sanders still faces huge obstacles in his second bid for the Democratic presidential nomination. Key among them is a history of resistance in 2016 from core groups in the party, including African Americans and voters who identify as partisan Democrats.

Sanders this week quickly demonstrated his greatest asset as a candidate: a passionate grassroots following that includes a massive base of small-dollar online donors. On Wednesday he reported that, in the first 24 hours after his announcement, he raised nearly $6 million online, far more than any of his rivals did after entering the race. He’s in a stronger position than in 2016, too, in the internal party debate. As Sanders noted in his announcement-day interview with CBS, more of the Democratic Party’s leaders, including several of his 2020 competitors, have moved toward positions he took in the last presidential campaign, supporting a single-payer health-care system and free four-year public college. “All of those ideas and many more are now part of the political mainstream,” Sanders crowed during the interview.

It’s unquestionable that more Democrats are supporting those ideas than when Sanders aired them in 2016. But all the policies remain contested: Klobuchar, for one, has already rejected both single-payer and free tuition. Other potential candidates targeting more moderate voters, such as Biden and several former governors eyeing the race, would be almost certain to follow. (It’s also worth noting that the Democratic-controlled House is unlikely to pass legislation on either matter.) Even some of the candidates who have echoed Sanders’s overall goals are likely to challenge some of his specific proposals as unaffordable or excessive, as Booker has done by rejecting Sanders’s call to virtually eliminate private health insurance.

In other words, Sanders hasn’t won the war of ideas in the party nearly as much as he’s suggested. In fact, he’s virtually certain to face tougher scrutiny over his agenda than he did in 2016, when Clinton made the misguided strategic choice not to criticize his proposals as undesirable or unaffordable, but only as unlikely to pass Congress. Sanders probably won’t receive such deference again.

The biggest question for Sanders is whether he can expand the coalition that he mobilized in 2016—or even, in this enormous field, maintain the advantages he displayed last time. Sanders ran extremely well in 2016 with three groups. Young people topped the list: Sanders won most voters age 30 and younger in 25 of the 27 states with exit polls. Looking across the entire contest, he carried fully 71 percent of younger voters, according to a cumulative analysis of all 27 exit polls by CNN polling director Jennifer Agiesta. That was an even higher percentage than Barack Obama carried among younger voters in 2008.

Sanders was also extremely strong with primary voters who identified as independents rather than partisan Democrats. He carried them in 24 of the 27 states with exit polls (losing them only in three southern states), and won nearly two-thirds of them overall in Agiesta’s cumulative analysis. He also ran very well among white men without a college degree—carrying slightly more than three-fifths of them overall—while posting a more modest advantage among their college-educated counterparts.

But Sanders faced persistent resistance from other groups central to the Democratic coalition. African Americans led that list: Clinton carried black voters in all 22 states where they had a high enough population to measure in the exit polls. In all, the cumulative analysis found that Clinton won more than three-fourths of both black women and black men. Sanders did narrowly beat Clinton among black voters younger than age 30, but was obliterated by older African Americans. And while he performed somewhat more competitively among black voters outside the South, Sanders did not win even a third of them in any state, according to the exit polls.

Sanders, who has never formally identified with the Democratic Party, also consistently struggled among primary voters who consider themselves partisan Democrats, which is something of a hurdle for someone trying to win the Democratic nomination. Clinton won self-identified Democrats in every state with an exit poll except Vermont and New Hampshire, Sanders’s backyard, and Wisconsin, where they tied. In the cumulative result, she beat him among Democrats by nearly 2 to 1. Sanders’s weakness with Democrats partly reflected his troubles with African Americans, but Clinton posted a solid lead among white Democrats as well.

In 2016, Sanders also faced big deficits among voters older than age 45 and moderates, and more narrow disadvantages among several other groups: voters who described themselves as somewhat liberal (as opposed to “very”), college-educated white women, and white women without a college degree. And while Sanders ran better with Hispanics than he did with African Americans, Clinton still carried just over three-fifths of them.

These persistent patterns of support create several interlocked challenges for Sanders. The first is that the groups that liked him most are generally smaller than the ones most skeptical about him. Self-identified Democrats, for instance, cast about three-fourths of the primary votes in 2016, compared with only about one-fourth from independents and self-identified Republicans. (Many states have open presidential primaries where voters don’t have to be registered with a particular party.) Voters under 30 amounted to 17 percent of all 2016 voters, while voters over 45 constituted 60 percent. And non-college-educated white men cast only about one-eighth of the votes in 2016, compared with about one in four that were cast by African Americans.

One Sanders adviser, who asked not to be identified while discussing internal strategy, acknowledged that the groups drawn to the senator tend to be smaller. But the adviser said that disadvantage could be offset. “Bernie’s path is, we do better with noncollege voters, Millennials, independents, Latinos,” the adviser said. “The good news is, there are fewer candidates vying for those votes. Yes, those groups are smaller, but we have less competition for them.”

Still, Sanders will face much more competition for young people than he did during his last campaign, when his only rival was Clinton, who struggled to relate to younger voters in both the 2008 and 2016 primaries. This time, several other candidates, led by O’Rourke if he runs, are all likely to target younger voters. “I think Harris and Beto, in particular, could really pick off a lot of Bernie’s potential younger supporters, but others like [New York Senator Kirsten] Gillibrand could as well,” says Andrew Baumann, a Democratic pollster who has extensively studied political attitudes among young people. “And I’d think that Biden would get his share, too, even though he’s another old white guy.” Holding young people is crucial for Sanders because independents, his other best group, are not as great a factor in the states that allow only registered Democrats to participate in primaries.

Sanders’s related challenge is that with California moving its primary to Super Tuesday, on March 3, next year’s calendar is even more front-loaded than it was before toward states with large numbers of the minority voters he’s struggled with. From Nevada and South Carolina in mid-February 2020, through the Florida and Arizona primaries in mid-March, the Democratic calendar is dominated by Sun Belt states with large populations of Hispanics, African Americans, or both. If Sanders can’t perform better with those groups than he did last time, he could face the same insurmountable delegate disadvantage that he confronted after Clinton routed him across the South in 2016.

In a race wherein three or more candidates are viable over an extended period, Sanders’s base among young people, independents, and white progressives could allow him to survive alongside opponents primarily targeting white moderates and minority voters. But if he can’t build on that base, he might again fall short in virtually all the most diverse states, which includes almost all the largest states on the map. Three years after he shocked Clinton and the Democratic establishment with the strength of his insurgency, Sanders faces new rivals—but very familiar political challenges.

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