With his unexpected victory in Indiana and Donald Trump becoming the presumptive Republican nominee, Bernie Sanders faces a tough decision in the coming days. Should the Vermont senator drop out and help unite the Democrats to fight Trump? Or does the continued strength of Sanders’s movement mean that he should carry the fight to the convention, even if he is highly unlikely to win?

Despite winning the popular vote in Indiana, Sanders won’t see any substantive improvement in his delegate count because delegates are distributed proportionally. Moreover, given Clinton’s slim lead among pledged delegates and her overwhelming lead among the superdelegates, Sanders would need to win by much larger margins to close the gap, let alone defeat Clinton.

Sanders has been making a dubious argument for why he should stay in the race: that the Clinton-pledged superdelegates in states he’s won should flip to him, and because he’s supposedly a more viable general election candidate than Clinton. The former still wouldn’t give him the delegate lead, though, and current polling is hardly predictive of who is more electable in November.

In truth, Sanders has a better argument for the staying in the race, one that was made by Clinton and her followers in 2008: When you have a mass movement, you owe it to your supporters to fight as long as possible—to fight, in the words of Bill Clinton, “until the last dog dies.” As Howard Wolfson, Clinton’s onetime communications director, told Politico about the 2008 race, “Your head told you the math didn’t add up, but your heart said, we’re continuing to win states, we’re continuing to draw big crowds, and it’s very hard to walk away from a contest when you have millions of supporters who are clearly still determined to help you get elected.”

The fact that Sanders, this late in the race, can draw a majority of voters in Indiana means his revolution has yet to run its course. He owes it to his supporters in California and other late states to give them a chance to vote. Nor is a vote for Sanders meaningless, even if his loss is foreordained. The delegates he continues to rack up will give him a greater voice in the convention and allow his supporters to shape the party platform.

The counter-argument is that by continuing to fight, Sanders will weaken Hillary Clinton and make a President Donald Trump more likely. But recent history suggests otherwise. In 2008, exit polls in Indiana showed half of all Clinton supporters said they wouldn’t support Obama; in the end, Obama managed to unite the party. This year’s Democratic race is much more collegial, and polls show only a quarter of Sanders supporters say they won’t vote for Hillary Clinton.

The hotly contested 2008 contest ended up helping the Democrats win big in the general election by energizing the base. There’s no reason to think 2016 is different. Moreover, 57 percent of Democrats say they want Sanders to stay in the race. The party base, if not the party elite, appreciates what Sanders is doing by continuing his fight. He has every reason to listen to them.