Technically, she’s the frontrunner, holding her lead in national polls. But in the first two contests—Iowa and New Hampshire—Hillary Clinton is the underdog, losing to Bernie Sanders.

He represents a robust and growing Democratic left that has fallen in love with his anti-Wall Street truth-telling, although they may not know that early in his political career Sanders favored abolishing compulsory education, saying public schools “crush the spirits of our children.” He wanted to legalize all drugs, not just marijuana, and widen the entrance ramps on interstate highways so drivers could more easily pick up hitchhikers.

This is not urban legend. It’s spelled out in a Mother Jones article this year, “A portrait of the candidate as a young radical.” In ordinary times, this would be a mother lode of material to stall or stop Sanders’s momentum. But, as Clinton is finding out, Democratic voters eager for vengeance against Wall Street banks and hedge-fund managers don’t give a cat’s whiskers what Sanders did in the 1970s as the Liberty Union’s lefty candidate in a series of losing campaigns in Vermont, two for the U.S. Senate and two for governor.

Clinton can’t go after Sanders in the conventional way, dredging up his past and painting him out of the mainstream. When the pro-Hillary super PAC, Correct the Record, sent out an email last month to media outlets pointing to similarities between Sanders and the newly elected far-left leader of the Labour Party in the U.K., as though that were a bad thing, the Sanders campaign raised money off the alleged low-blow attack and whatever benefit accrued did not go to Clinton.

For Clinton when it comes to Sanders, silence is golden. She doesn’t even mention his name. “Her strategy is to treat him gently,” says a longtime Clinton insider, a view confirmed to The Daily Beast by a former New Hampshire Democratic Party chair, Joe Grandmaison. He says that could change, say in mid-January, when the primary is just weeks away, but there’s no reason for the Clinton campaign to take on Sanders now. “They want his support. They want to take advantage of the new people he arguably is bringing into the process. Niceness at this point is good politics.”

Reinforcing that strategy is the looming figure of Vice President Joe Biden, who probably wouldn’t be so tempted to enter the race if Clinton were doing better. And if he decides to run, staying in Sanders’s good graces becomes even more critical for Clinton.

Biden occupies the same political space as Clinton, and would divide the establishment vote, leaving Sanders the beneficiary with potentially enough delegates to win—or, more likely, play kingmaker—in a protracted battle between Clinton and Biden, says Bill Schneider, a political analyst and senior fellow at Third Way, a moderate think tank.

In Democratic politics, the Rev. Jesse Jackson played the role of kingmaker in the 1984 and 1988 elections when he ran in the primaries and all the pundits said he couldn’t win, just as the smart money does today with Sanders. Presumptive nominees Walter Mondale and Michael Dukakis steered clear of any direct confrontation with Jackson for fear of alienating the large and important constituency of African-American voters that looked to him for leadership.

“She has to deal with [Sanders] delicately, the way Dukakis dealt with Jackson,” says Schneider. Jackson won seven primaries and four caucuses, and it wasn’t until the Wisconsin primary in early April of the election year that Dukakis finally vanquished him.

That began extensive negotiations that included a head-to-head meeting that the media characterized as a summit. Schneider recalled to the Daily Beast that Dukakis invited Jackson to dinner and served him salmon, which the media mocked as elite cuisine—a Park Avenue meal—as tone deaf for the occasion as Dukakis’s reference about growing endive when he visited Iowa.

Still, it was all very polite and respectful, and Dukakis got his share of the African-American vote in the November election. “That’s the same thing Hillary has to do, she has to be polite, she has to be respectful, because this is a significant voice and vote in the Democratic Party,” says Schneider.

Sanders endorsed Jackson when he ran for president in ’84 and ’88, and to find out what Jackson thinks of Sanders as potential kingmaker in the current race, I reached him in New York, where he was attending Bill Clinton’s annual global summit.

“Who said Bernie couldn’t win? Who’s the ‘they’?” Jackson said, challenging the assumption behind my questions and saying, “Whoever gets the most votes wins.” He likes the way Sanders “takes positions that expand the conversation,” like he did when he ran in the ’80s calling for the recognition of Cuba and of Nelson Mandela in South Africa, positions that were not mainstream at the time.

If Sanders were to lose, Jackson continued, you want his voters to be “part of the expanded conversation and not part of the angry and alienated. It’s always a delicate situation,” he said, reflecting on his experience with Dukakis, and his belief that he should “at least be considered for vice president.” News reports at the time said Jackson had been “passed over” for the job twice, which meant he was considered, if only perfunctorily.

“I communicate with Hillary and Bernie,” Jackson said. “Many of their positions overlap, you know. They’re both very progressive Democrats.” Bill Clinton did the eulogy for Jackson’s mother, who died last month. And Jackson remembers Hillary from when she was with the Children’s Defense Fund and doing legal services in the Mississippi Delta.

“I have real affection for both of them—and Bernie endorsed me,” he said, by way of explanation that he’s not choosing sides.

Jackson is working in South Carolina, the third contest on the primary calendar, where he says there are a million people living in poverty in a Republican-run state that is refusing Medicaid expansion. Polls show Clinton leading with African-American and Hispanic voters in the state. That could change if Biden is in the race and is seen as “Obama’s man,” says Schneider.

A contentious contest between Biden and Clinton could extend well into next year with headlines that mirror Jackson’s experience in 1988 when, “What does Jesse want?” became a constant refrain. It’s not too soon to be thinking about an answer if things unfold the way the Clinton campaign and most political veterans imagine they will.

“Bernie may make your liberal heart go pitter-patter, but he won’t be your next president,” says a Democratic Party official, citing a recent Gallup poll that shows Americans are open to electing a president who is Catholic, a woman, black, Hispanic, Jewish, Mormon, gay or lesbian, an evangelical Christian, or Muslim (60 percent), even an atheist (58 percent). The lowest category of support (47 percent) is for a socialist.

Given those numbers, Sanders should be easy to defeat. But not now, and not by Clinton.