Hillary Clinton’s lead over Bernie Sanders in the Democratic primary is cushy, but other factors continue to dog her. The FBI has been interviewing former Clinton aides and may yet indict Clinton over material found in her emails. She recently lost to Donald Trump in a Rasmussen poll. And Sanders is continuing to win primaries, including in Indiana this week.

After that Indiana win CNN host Dana Bash questioned Sanders on why he isn’t dropping out, perhaps setting a new standard for establishment condescension. But with momentum still strong on Sanders’s side, with the possibility of Clinton’s indictment, and with the longstanding myth that Clinton is more electable disappearing, it’s more important than ever that Sanders stay in the race. In fact, the best part of the election may still lie ahead of him.

Mathematically, Sanders still has a shot at the nomination. It’s a longshot, though. He’s got to win about 65 percent of the remaining elected delegates and convince super delegates, who are party insiders and mostly in Clinton’s camp already, to switch sides and support him. He just may be able to do that if Clinton’s poll numbers continue to go down, which is the direction they’ve trended against both Sanders and Trump.

Even if he doesn’t manage that enormous upset, his campaign is continuing to add vital dialogue to the national conversation. One shudders to imagine the negative, non-substantive campaigns Trump and Clinton will run against one another. By staying in the race Sanders can prevent, or at least postpone, the conversation’s totally devolving to that.

Only by remaining in the contest can Sanders bring his message directly to the Democratic National Convention. And the more votes he gets between now and then, the more delegates he can send and the more impact he will have. John Nichols writes in The Nation that Sanders “is better positioned than any recent insurgent challenger to engage in rules and platform debates, as well as in dialogues about everything from the vice-presidential nomination to the character of the fall campaign.”

And Sanders’s influence is desperately needed in all those arenas. Clinton seems determined to run on a pro-establishment platform against Trump. She’s already forming alliances with top Republicans. Her decision to feature stuffy Republicans like Marco Rubio, Mitt Romney and Ted Cruz in an anti-Trump ad shows how little she understands what she’s up against. Their words won’t convince Republicans to shy away from Trump; Republican voters already rejected all of them.

When Clinton was asked about what she would do to reach out to Sanders supporters, she essentially said she wouldn’t do a thing. Because she’s winning she feels she shouldn’t need to offer them anything; they should just fall in line. Her eagerness to shrug off those pesky progressives and work with Republicans – emblemized by her campaign’s recent decision to place a red arrow pointing rightward in her logo – can be impeded if Sanders has a loud voice at the convention.

Sanders’s payoff for staying in the race may come even sooner than the convention. Between then and now there are still ten weeks and ten primaries. With no more real contests on the Republican side, perhaps the media will start to give serious coverage to the Democrats. They may have no choice if that’s where the only still-ongoing contest is. For the first time, the Democratic cycle could be sexier to the media than the Republicans.

On the Democratic side, Sanders has done a great job keeping the contest about issues, not personalities. The more exposure Sanders gets, the better his chances will be – not necessarily of winning the nomination, but of enlightening more Americans. Clinton’s empty calls to party loyalty and her abandoning of progressive virtues will be harder to pull off the longer Sanders shines a light on them.

Contrary to all the establishment cries that Sanders is making Clinton a weaker general election candidate, his continued presence in the race should be making her a better one. All she needs to do is let go of her Trump-sized ego and listen. It’s Clinton who wants to embrace the hated establishment. It’s Clinton who wants to ignore the mobilized young voters Sanders brought to her party. It’s Clinton who wants to fight Trump on his own terms, a battle she almost certainly can’t win.

However slim his chances may be, calls for Sanders to quit are insulting. Clinton has no idea what she’s in for against Trump – his crossover appeal, his viciousness, the fact that every attack makes him stronger. Instead of chastising Sanders she should recognize that his progressive populism, and not her centrist politics-as-usual, is the only antidote against Trump’s fascistic rise. The country’s fate may depend on the DNC’s ability to receive and adopt that message, and they never will if Sanders drops out.