When Sen. Bernie Sanders, I-Vt., had two heart stents inserted into his arteries in early October, media pundits were quick to foresee the end of his pioneering, movement-based candidacy. Some questioned why it took three days for his family and campaign to confirm the details of his medical condition and others wondered whether age and health would be important factors in his candidacy. Given the documented media bias against Sanders, it is certainly not surprising to see Sanders’ health scare exploited to undermine his candidacy. (Sanders, on the other hand, in his typical fashion, exploited his situation to demand that health care ought to be “a human right.”)

Los Angeles Times opinion writer Rich Benjamin pushed the bias further by saying, “any perception of fatigue and frailty can undercut his effectiveness in competing for the nomination and in the dogfight against Trump if he does beat the rest of the Democratic field.” Benjamin demanded that it was time for “Bernie and his bros”—using a sexist, racist and discredited smear that assumes Sanders’ supporters are mostly pig-headed white men—“to get behind Elizabeth Warren.” In fact, men and women are roughly evenly split among Sanders’ supporters, and people of color are more likely than whites to back him.

Benjamin is echoing a sentiment that has been gaining traction: that Warren is a good enough emulation of Sanders and has adopted enough of his progressive policy proposals for Sanders’ supporters to unreservedly support her. But while a Warren nomination would certainly be a strong sign of progress, particularly in the era of Donald Trump, there are serious distinctions between Sanders and Warren that should not be dismissed.

For example, on health care, although they both back the idea of a “Medicare for All” plan, Warren and Sanders do not take identical positions. Health care is the most important issue for the American electorate. During Tuesday’s Democratic presidential candidate debate, Warren repeatedly avoided admitting that backing a Medicare for All plan would mean that taxes would go up across the board. She sidestepped questions twice, saying, “I will not sign a bill into law that raises their costs, because costs are what people care about.”

But in fact, people care about getting the health care they need more than anything. According to a new poll released on the same day as the debate, “Fifty-six percent of Americans think providing access to affordable health care coverage for all Americans is the responsibility of the federal government, and two-thirds favor the creation of a national, government-administered health insurance plan similar to Medicare that would be available to all Americans.” Vox.com writer Tara Golshan explained that although Warren has endorsed Sanders’ health care plan, “she speaks about Medicare-for-all more in terms of expanding public options for health care, rather than eliminating private insurance altogether.”

Sanders, on the other hand, was far more candid about the cost of his plan during the debate, saying, “I do think it is appropriate to acknowledge that taxes will go up. They’re going to go up significantly for the wealthy. And for virtually everybody, the tax increase they pay will be substantially less — substantially less than what they were paying for premiums and out-of-pocket expenses.” By acknowledging that taxes will go up while premiums, co-payments, deductibles and “all out-of-pocket expenses are gone,” Sanders was far more honest about what his bill to expand Medicare to every American would entail while also demolishing the right-wing argument about high costs. Later in the debate, he went further and slammed the Democratic Party, challenging it to have “the guts to stand up to the health care industry, which made $100 billion in profit.”

There are differences in other policies too. For example, Sanders’ plan to tax the wealthiest Americans goes much further than Warren’s. His tax rate for billionaires is more than twice that of Warren’s, leading one commentator to declare that Sanders’ plan to tax extreme wealth “makes Warren’s wealth tax look moderate.” Sanders has even said he doesn’t think billionaires should exist.

It has become more and more apparent that Sanders is the only Democratic candidate to have a lengthy track record on progressive politics, compared to those who have discovered their progressive backbones more recently, because they know it plays well to the party’s left-leaning base. Seven years ago, Warren did not back Medicare for All, and 23 years ago she was a registered Republican. In fact, she maintains she is an avowed capitalist. Meanwhile, Sanders has been backing the idea of a Medicare plan expanded to all Americans for at least 10 years. He has been calling himself a socialist for decades, and he most recently distinguished himself from Warren’s self-proclaimed capitalist label in an interview.

When Sanders ran for the Democratic presidential nomination in 2016, media outlets ignored him until he began winning primaries, and even then, experts routinely underestimated his pull and popularity. Progressives were thrilled to finally see a bona fide leftist candidate on a national stage echoing the issues that we longed to hear about, analyzed in ways that targeted corporate profiteers.

After the election ended, the movement that was borne from his candidacy flourished and proliferated into multiple organizations determined to challenge establishment politics from inside and outside the electoral system. Among the successes of that movement was the 2018 election of the outspoken and staunchly progressive Rep. Alexandria Ocasio-Cortez of New York.

While recent polls show Sanders’ popularity as a candidate dipping a few percentage points behind Warren, his performance this week during the Democratic debate (including his characteristic dismissal of concern over the state of his health, saying only that he was “healthy” and “feeling great”), may bump his numbers up in the next poll. Perhaps even more important is the announcement that Ocasio-Cortez will be endorsing his candidacy. Both Warren and Sanders had sought the endorsement of the young and very popular progressive Democrat, and now that Sanders has clinched it, it may well boost his standing.

Minnesota Rep. Ilhan Omar and Michigan Rep. Rashida Tlaib, who are considered part of the four-member “squad” of prominent progressive congresswomen of color, have also decided to throw their weight behind the Vermont senator. Sanders and Omar just co-sponsored a bill to feed all schoolchildren three free meals a day regardless of income. Clearly Ocasio-Cortez, Omar and Tlaib see a distinction between Warren and Sanders.

There is one thing Warren has going for her over Sanders: She’s far more charismatic than he is. At a recent LGBTQ event in Los Angeles, Warren won over the crowd when she was asked how she might respond to a supporter who claimed that marriage should be between one man and one woman. She replied, “I’m going to assume it is a guy who said that. And I’m going to say, ‘Well, then just marry one woman. I’m cool with that.'” With the perfect timing of an improv artist, she waited for applause and added, “Assuming you can find one”—which of course resulted in even more applause.

Yes, Warren’s candidacy would be huge step in the right direction for the United States in the Trump era—especially if she were the most progressive front-runner in the race. But she’s not. In fact, she is arguably being pulled to the left by Sanders’ candidacy. CNBC’s Jim Cramer suggested that if Sanders dropped out of the race, “she doesn’t have to be worried about that [far-left] flank anymore.” So, do progressives want the candidate who may be feeling pressured to move to the left or the person whose candidacy is setting the progressive standard?