Bernie Sanders, in Pennsylvania. Photograph by Jeff Swensen/Getty

If my social-media feeds are any indication, Hillary Clinton’s big victory in the New York Democratic primary has left many of Bernie Sanders’s supporters feeling upset, angry, and disillusioned. Some are blaming voter fraud, others are blaming the media, and others are simply aghast. On Facebook, one Bernie enthusiast asked, how can so many people have voted for Hillary? I didn’t meet anybody who was voting for her.

These reactions are understandable. If Sanders had defeated Clinton on her own turf, the inevitability narrative of her candidacy would have been shattered, and the media and the Democratic Party would have been in an uproar. Now that Sanders has lost decisively, he is in a bind. To assemble a majority of the pledged delegates going into the Party's convention, he needs to win about fifty-eight per cent of the delegates in the remaining contests. That represents an enormous challenge, especially since he seems likely to suffer more losses next week in states like Delaware, Maryland, and Pennsylvania. Increasingly, it looks as if Sanders is fighting a battle that he can’t win.

So what conclusions, if any, can he and his supporters draw from what happened in New York?

There is no reason why Sanders should accede to demands from some Clinton supporters for him to drop out. Having started from nothing and finished ahead of Clinton in fifteen states, the Vermont senator has the right (and indeed the obligation to his supporters) to carry on through June 7th, when California, New Jersey, and four other states will vote. “Sanders has voiced the concerns and energized millions of young people, many of them voting for the first time,” an editorial in the Times pointed out on Wednesday. His presence in the race has “forced the party to go deeper on addressing issues like wealth inequality, college tuition costs and the toll of globalization—important points of distinction with Republicans. What’s more, Mr. Sanders’s commitment to small individual contributions has put the lie to Democrats’ excuses that they, too, must play the big money game to win.”

Claims that Sanders is dividing the party and making a Republican victory more likely have little foundation. The thing that really matters is what happens at the convention in July, and afterward. As long as Democrats come together to support their candidate and oppose Donald Trump, or whoever wins the Republican nomination, the divisions of the primary season will be largely forgotten.

So Sanders and his supporters should keep going for now. And they should probably avoid jumping to the conclusion that the New York primary was stolen from them. What happened in Brooklyn, where a hundred and twenty-six thousand Democratic voters were removed from the polls, was a disgrace that demands a much fuller explanation than the one the city’s Board of Elections has trotted out. Initially, it claimed that staffing issues were to blame. On Wednesday, its executive director, Michael Ryan, insisted that “no one was disenfranchised”—a claim I’d like to see him explain to my wife, a registered Brooklyn Democrat who has voted in the borough in every Presidential election since 1996, and many local elections, too, but who discovered on Tuesday that she had been eliminated from the electoral rolls because she was “inactive.”

The most benign explanation is that the missing voters were a case of bureaucratic incompetence. Given the scale of the problem, it represented a scandalous neglect of voters’ rights and due process. (Did anybody seek to contact the voters before purging them? Apparently not.) Right now, though, there is no evidence that Sanders supporters were singled out for exclusion. The people purged from the polls appear to have been spread across Brooklyn, which Clinton won by almost sixty thousand votes. Plus, even if Sanders had somehow carried the borough, he would have lost all the other big counties in and around New York City.

As I emphasized in the post I wrote after the results came in, the main reason that Clinton won is that she racked up big majorities among some key constituencies of today’s Democratic Party—women, blacks, Hispanics, and affluent, highly educated whites. Sanders carried the under-thirty demographic and white men—and that was about it.

If future left-liberal candidates are going to improve on Sanders’s performance, they and their supporters will have to acknowledge this reality and adapt to it—a process that doesn’t have to be self-lacerating. Although they suffered a bitter disappointment on Tuesday, Sanders and the progressive movement that he represents have accomplished a great deal. In addition to drawing new voters to the Democratic cause and shaping its political agenda, they have established the left wing of the Party as a force that can’t be ignored or belittled. Obviously, that isn’t enough for them, though. Progressives want the Democrats to adopt their policies and their candidates wholesale. Before that can happen, they will have to overcome some big hurdles.

One of their priorities should be to press for election procedures that are more open, and other reforms. If independents had been allowed to vote on Tuesday, and same-day registration had also been permitted, the result would probably have been closer. As it was, the election was restricted to registered Democrats. There was also no early voting, and the registration period expired nearly a month before the election. “The fact is, New York does have some of the worst voting laws in the country,” Ari Berman wrote, for The Nation. But, he added, “incumbent politicians in both parties have resisted calls for electoral reforms.”

With the clout afforded by his large number of delegates, Sanders could use this year’s convention to demand open primaries, same-day registration, and the abolition of superdelegates—a plan of action that is indeed being proposed by some of his supporters. “Democratizing the Democratic Party is not a revolutionary act, but it could open up institutional space for a revolutionary politics,” Jesse Myerson, a New York socialist activist, wrote at In These Times, on Wednesday. Restrictive voting rules and superdelegates exist largely to snuff out insurgent candidates. Getting rid of these would make it easier for a future Sanders to win.

Structural reforms will only go so far, however. Even if all of the primary elections had been open ones, Sanders would still be trailing Clinton because of the difficulties he has encountered in attracting minority voters. In 2012, about forty-five per cent of the people who reëlected Barack Obama were nonwhite. Within a decade or so, a majority of the Democratic Party will probably consist of minorities. Left-liberals like Sanders, if they are to be successful, simply have to attract more support from blacks and Hispanics.

Sanders himself has recognized this, of course. He began his campaign focussed “almost exclusively on themes of class, inequality and political corruption,” Michael Lind noted in the Times last weekend. “But because he is running for the Democratic presidential nomination, he has had to put greater emphasis on other issues, including racial disparity in policing and sentencing and the environment and immigration.” In some places, Sanders’s efforts to win over minorities have met with success. In the Illinois primary, for example, he attracted almost half of the Hispanic vote, according to some polls. But in New York, where he came up against a centrist who has spent more than two decades cultivating ties to minority voters, the result demonstrated how much outreach work is left to be done.

Taking over a major political party, which is what Sanders and his supporters have set out to do, is never easy. Once the party establishment realizes what you’re up to, it will do all that it can to thwart you. (Just ask Trump.) When progressive Democrats look at the list of states that Sanders has won and the way that young voters have reacted to what he is saying, they have reasons to be encouraged about the future. But the New York primary came as a reality check, and its lessons can’t be ignored.