– Sen. Bernie Sanders’ growing momentum in the Democratic presidential race has put mounting pressure on Sen. Amy Klobuchar to coalesce with her centrist rivals around one alternative to the leftist icon from Vermont.

Klobuchar has shown no sign she’ll quit the race ahead of Saturday’s South Carolina primary or next week’s Super Tuesday contests, when voters in 14 states including Minnesota go to the polls. “We’re pretty excited about the road ahead,” she said Monday night at a fundraiser in a Charleston steakhouse.

But a sixth-place finish in the Nevada caucus, her struggle to get footing in South Carolina, and single-digit poll showings in several big Super Tuesday states has some Democrats questioning why Klobuchar is still contending for the Democratic presidential nomination.

“I think she needs to drop out. At this point, any vote for Amy Klobuchar is helping Bernie Sanders,” said Bakari Sellers, a prominent South Carolina Democrat. A former state lawmaker and candidate for lieutenant governor, Sellers had originally supported Sen. Kamala Harris for president but is now publicly neutral.

Sanders’ wins in Nevada and New Hampshire, and a close second-place finish in Iowa, had him holding a healthy lead in the delegate count heading into Super Tuesday, when more than a third of all delegates will be totaled. That’s stoking fears in the Democratic establishment that a 78-year-old, self-professed democratic socialist with recent heart problems may not be best to lead their national ticket.

But the first three state contests have produced no clear alternative. In addition to Klobuchar, former Vice President Joe Biden, former South Bend, Ind., Mayor Pete Buttigieg, and former New York City Mayor Michael Bloomberg are all jostling for centrist support.

Klobuchar trails Buttigieg and Biden in delegates so far. Bloomberg was not on the ballot in several early states, but he has leveraged his personal fortune to thrust himself into contention with a heavy TV advertising blitz.

The other billionaire in the race, businessman Tom Steyer, finished narrowly ahead of Klobuchar in Nevada and has been investing heavily in South Carolina as well.

On Sunday, campaigning in the Super Tuesday state of Arkansas, Klobuchar dismissed the notion that she should consider dropping out. “Why would I get out? That’s not even a close call for me,” Klobuchar told reporters. Campaigning in Fargo the same day, she said, “This is a campaign that believes in underdogs.”

The following day, Klobuchar’s campaign released a “state of the race” memo pushing back against arguments that Klobuchar has no path to the nomination.

“Just as Amy has shown on the debate stage, she is the best person to take on Bernie Sanders and the best candidate to beat Donald Trump,” her campaign manager, Justin Buoen, wrote. He announced the campaign was investing more money in TV ads in Super Tuesday states; a super PAC supporting Klobuchar is also airing ads in select states.

A week earlier, Bloomberg’s chief campaign strategist wrote in a memo that was leaked to the press that “Bernie is likely to open up a delegate lead that seems nearly impossible to overcome” if Klobuchar, Biden and Buttigieg are all still in the race on Super Tuesday. Klobuchar herself criticized that memo at last week’s debate in Nevada.

Klobuchar has been a persistent critic of Sanders’ Medicare for All proposal. And she seemed to take a veiled swipe at Sanders on Monday night when her campaign released a report from her doctor saying Klobuchar, 59, “is in very good health. She does not have any health conditions that would impair her ability to perform the duties of the presidency.”

Sanders had a coronary episode in October that was later reported to be a heart attack. He has subsequently refused to release detailed medical records.

As the primary battle moves to South Carolina, the polls and the pundits suggest a showdown for the top spot between Sanders and Biden, once considered the front-runner. As the candidates gathered Tuesday night at Charleston’s Gaillard Center for the latest debate, protesters, journalists and gawkers circled outside under a drizzle, waiting to see who might emerge as Sanders’ top challenger.

Few picked Klobuchar. Joe and Georgia Byrd, a photographer and a writer who live nearby, walked over to see the spectacle wearing Biden T-shirts. “He’s our closest connection to the Obama administration,” Joe Byrd said.

Georgia Byrd said she liked Klobuchar’s previous debate performances and noted that her adult daughter is especially fond of her. But, she said, “Some of these candidates have to start dropping out. They are diluting their message. I think it’s bad for the party. And I include Amy on that list.”

Joe Byrd surmised that at this stage it would be unlikely for any candidate to exit. “At this point you might as well see how you do on Super Tuesday,” he said.

But some prominent national voices have begun to raise questions, among them Washington Post columnist Jennifer Rubin, a conservative critic of Trump who has written admiringly about Klobuchar as the Democrats’ best shot in November. But on Tuesday she wrote that it’s it time for Klobuchar to go.

“She has run a spirited race, but continuing on at this rate will only diminish her brand and elect a candidate she has pointed out is exactly the wrong person to defeat Trump,” Rubin wrote. “Those close to her need to deliver some tough love.”