No sooner had Sen. Ted Cruz of Texas exited the Republican primary on Tuesday night than Democrat Hillary Clinton’s partisans on social media began calling for Sen. Bernie Sanders of Vermont to follow suit.

Sanders supporters answered those calls with a hashtag that quickly started trending on Twitter: #DropOutHillary.

With his victory in Indiana, Sanders seems all but certain to remain in the race for at least another month, taking his insurgent presidential campaign to the California primary on June 7. But there is one thing he will definitely leave behind if he ultimately abandons the Democratic nomination fight: an army of online foot soldiers unmatched in size, influence and capabilities, more than ready to join the next battle.

The only question is whether that battle will involve Clinton.

According to Personal Democracy Media, which studies the intersection of politics and technology, roughly 9 million Sanders supporters have organized through hundreds of Facebook pages, Reddit forums and Slack channels. And Sanders’ digital corps is not some loose network of supporters informally sharing articles and videos. It is a driving force behind his campaign, soliciting tens of millions of dollars in donations an average of $27 at a time, routinely mobilizing volunteers to perform impressive feats of organizing, and developing cutting-edge technology to aid Sanders’ run.

If Clinton can harness even some of the power of this group, it could provide an important lift for her in a bruising general election in which social media is certain to play a prominent role. It not only would help her reach younger voters, among whom she has performed miserably in the primaries, but could also fortify her for the digital trench warfare she can expect if she faces the Twitter-adept Republican favorite, Donald Trump, in the fall.

But Clinton’s place at the forefront of her party’s establishment could make her a tough sell to an online community whose members often identify themselves as revolutionaries more than as Democrats.

“Turning Sanders for President into a direct drive for Hillary is probably doomed,” said David Fredrick, who co-founded a Reddit forum, SandersForPresident, that has more than 230,000 subscribers. “It would alienate a lot of our users and cause us to lose a lot of the momentum we’ve been able to develop over the last two years.”

Clinton’s aides say they hope that at least some in Sanders’ online army will ultimately get behind her — particularly now that they seem almost certain to face the stark choice between Clinton and Trump.

But bringing around this vocal and defiant core of Sanders supporters may not be easy. One need only surf through the dozens of Reddit forums devoted to Sanders, or the comments on his Facebook page, to find countless examples of ambivalence, if not outright hostility, toward Clinton.

On Twitter, the hashtags #BernieOrBust and #StillSanders have been used more than a million times since January, according to Zignal Labs, an analytics company that tracks social media. Some Sanders supporters have even co-opted the Republican hashtag #NeverHillary.

Already, some of the technology professionals who volunteered countless hours to the Sanders campaign are turning away from Clinton and toward progressive candidates further down the ballot.

“If Bernie doesn’t win, we need to still carry that torch, as it were,” said Jon Hughes, a developer who built voteforbernie.org and helped organize the campaign’s digital volunteers. “And there are a lot of great candidates out there that can do that.”

Sanders was something of a social media savant even before starting his campaign: Aides say he had more Facebook followers than any other member of Congress except Rep. Paul D. Ryan, R-Wis., now the House speaker. But once Sanders’ campaign began, his message started to resonate with young, tech-oriented voters, who helped propel him to improbable victories in a number of primaries and caucuses by not only championing his candidacy, but also building much of his campaign’s digital infrastructure.

A group called Coders for Sanders developed an app for canvassers, an interactive event map for Sanders’ website, and the app his campaign used to track and monitor the Iowa caucuses. Volunteers also built a tool to make it easier to give money to Sanders; his campaign says 94 percent of the $200 million he has raised has come online. At least two of those volunteers were brought on to the campaign’s staff: Aidan King, its social media liaison; and Zach Schneider, who oversees its web development work.

“For this campaign, social media hasn’t just been about spreading a message,” said Kenneth Pennington, Sanders’ digital director. “It’s been an avenue for broader participation.”

The Sanders campaign and its network of online supporters became closely intertwined, with staff members often making requests through social media. Before the New York primary last month, campaign aides asked the Reddit page’s subscribers to make 2 million calls on Sanders’ behalf; they made 3 million.

“The value of the online army he’s built should not be underestimated,” Stephanie Cutter, a former deputy campaign manager for President Barack Obama, said of Sanders’ followers. Whether that army chooses to rally behind Clinton, she added, depends largely on Sanders: “How and when does he endorse Secretary Clinton, and what type of leadership role is he going to play to bring his supporters along?”

Yet even an enthusiastic endorsement from Sanders may go only so far. For all the cooperation between the campaign and its online foot soldiers, they remain a sprawling, decentralized group over which Sanders exerts little control.

“It’s not an army, it’s a swarm,” said Micah L. Sifry, a co-founder of Personal Democracy Media. “They’ve flocked to Sanders in response to the moment of opportunity he seized in the last year, but as the primary comes to its conclusion, they won’t be commanded by Bernie or any other general.”

They have already demonstrated their unruliness, with the rise of the so-called Bernie Bros, known for aggressive online harassment of Clinton’s supporters. And though Sanders’ prospects have dimmed, the anti-Clinton rhetoric from some of his backers has grown more heated.

Clinton’s supporters are fighting back. Citing online interactions with the Bernie Bros, a pro-Clinton “super PAC,” Correct the Record, recently announced that it would spend $1 million to respond “quickly and forcefully to negative attacks and false narratives” about Clinton.

Pennington, of the Sanders campaign, said it was too early to speculate about what Sanders’ online supporters would do if he ended his campaign. But some of them are already beginning to lend their efforts to progressive candidates in different races.

Hughes, the founder of voteforbernie.org, has created another site, grassrootsselect.org, to identify and promote liberal candidates through some of the same digital channels used by the Sanders social media movement. Developers who volunteered for Sanders are also working with Brand New Congress, a new political action committee devoted to electing lawmakers who share Sanders’ policy views in the 2018 midterm elections.

“Progressive candidates usually do not have the same reach or accessibility towards apps or resources to help jump-start their campaign,” said Rapi Castillo, a software developer and member of Coders for Sanders. “We could have a lot of impact.”

Of course, the more willing Clinton is to incorporate some of Sanders’ policy positions into her campaign, the more success she will have wooing his supporters. At least up to a point.

“She can win some of them with honey, but if she tries to command them, they’ll just sting her,” Sifry said. “As swarms may do.”

© 2016 The New York Times Company