Kamala Harris says she would like to pass a single-payer health care bill.

It’s just not clear how serious she is about it.

During a town hall event in Iowa on Monday, CNN’s Jake Tapper pointed out that the California senator, who is running for president, had co-sponsored the Medicare for all bill written by Bernie Sanders, which would put all Americans on one government-run health plan and ban private insurers from offering competing coverage. “So for people out there who like their insurance, they don’t get to keep it?” Tapper asked.

Harris, to the surprise of many, leaned into the question with a firm no. “Let’s eliminate all of that,” she said of private insurers. “Let’s move on.” The candidate seemed to be planting a flag on the single most important question hanging over Democrats’ health care plans going into 2020: Would they embrace a Bernie Sanders–style single-payer plan that mostly eliminates private insurance? Or would they run on one of the many other proposals lawmakers have created to expand government coverage, which all have been described under the rubric of “Medicare for all”?

Harris’ answer thrilled left-wing activists, who have treated single-payer as a key litmus test for candidates. “There is no viable path to the Democratic nomination for someone who does not support single-payer health care,” Sean McElwee, founder of Data for Progress (and the guy who made “Abolish ICE” famous) told NBC News. “It’s done.”

But maybe it isn’t. By Tuesday, Harris’ team seemed to be creating a bit of wiggle room. According to CNN, one of her advisers “signaled that the candidate would also be open to the more moderate health reform plans, which would preserve the industry, being floated by other congressional Democrats.” Her national press secretary then proceeded to walk back the walk-back. “Medicare for all is the plan that she believes will solve the problem and get all Americans covered. Period,” Sams told CNN. “She has co-sponsored other pieces of legislation that she sees as a path to getting us there, but this is the plan she is running on.” Harris’ Senate colleagues also tried to help her thread the needle.

So guess what - Senators can support more than 1 way to achieve universal health care. I introduced a Medicare buy in bill, but I cosponsored the @brianschatz Medicaid buy in bill. @KamalaHarris supported my bill but she also cosponsored Medicare for All. It's all cool, friends. — Chris Murphy (@ChrisMurphyCT) January 30, 2019

All of the back and forth may seem a bit confusing. But at the root, Harris’ implicit position seems to be very simple: When it comes to Medicare for all, she’s willing to pass the most left-wing bill that’s politically feasible.

The problem with this stance, of course, is that single payer is currently a political long shot at best, for reasons Vox’s Dylan Scott has written about at length. One key hurdle is the Senate, where a true single-payer plan would need to get past the filibuster. Democrats could always eliminate the 60-vote threshold if win a majority in the chamber. But even if they did—and that’s a big if—it’s unclear that enough senators would vote to scrap the entire employer-based insurance system. “That is a massive part of the American economy. There is a system in place for funding it,” Illinois Sen. Dick Durbin, the Senate’s second-ranking Democrat, told CNN. “It would take a mighty transition to move from where we are to that.”

Fundamentally, the "sure, if we can” approach feels like a cop-out.

It doesn’t help matters that, as of now, single payer doesn’t seem to poll very well. The catchphrase “Medicare for all” is broadly popular, even among Republicans. But polling by the Kaiser Family Foundation has shown that Americans only have a fuzzy idea of what it actually would entail. Most mistakenly believe it would allow them to keep their current private plan, if they wanted. And support for a national health care plan drops to just 37 percent once people are told that it would also eliminate private insurance companies. The Pew Research Center has reached similar results: In September, its polling showed that only 49 percent of Democrats and Democrat-leaning independents think the U.S. should deliver health insurance through a single national program; among all adults, just 31 percent thought so. Described in detail, Bernie-style single payer may actually be one of the few things less popular than Donald Trump.

That, of course, could change if Democrats go out and make a vocal case for it. Pew’s polling shows that single payer has gained support over time, no doubt thanks to Sanders’ efforts. But if a president wants any hope of turning the U.S. health care system into a more generous version of Canada’s, they’re going to have to sink much of their energy and political capital into evangelizing it.

Is Harris willing to do that? It’s not clear. Presidents typically have a limited window of opportunity to pass major legislation. And on Monday, Harris told her town hall audience that her first goal as president would be to pass the LIFT Act, a bill that would essentially give working families an additional allowance of up to $500 a month. It is a wildly ambitious piece of legislation (with some notable problems) that would cost roughly $3 trillion over a decade, as it’s currently written. Now, it’s possible Harris truly believes she’ll be able to pass a once-in-a-generation upgrade to the welfare state, then end private insurance as we know it as a follow-up act. But the idea sort of strains credulity.

This is why the Harris team’s muddled follow-up on single payer—sure, why not, if we can—raised some concern among the left, where activists are worried that Democrats will pay lip service to single payer before dropping it. As Waleed Shahid, communications director for the activist group Justice Dems, put it:

A public option buy-in is VERY different than single-payer, Medicare for All.@KamalaHarris should clarify if she's in favor of a public option, some other incrementalist approach, or single-payer. Because she told CNN she supports getting rid of for-profit insurance companies. https://t.co/0LtTFF9EJr — Waleed Shahid (@_waleedshahid) January 30, 2019

To be fair to Harris, she isn’t the only Democrat who seems to taking the “sure, if we can” approach to single payer. Other probable candidates, such as Kirsten Gillibrand and Cory Booker, have endorsed Sanders’ single-payer proposal along with more moderate ideas floating through the Senate.

But fundamentally, it feels like a cop-out. It’s reasonable for a candidate to say that they support single payer, and that they are willing to lay their presidency on the line to achieve it. After all, that’s what a significant chunk of the party, including much of its progressive base, appears to want. It’s equally reasonable for a candidate to oppose scrapping private insurance at this point, given that the issue divides Democrats, is unpopular with the wider public, could take up essential time needed to address issues like climate change, and isn’t actually essential to establishing universal health insurance. (In the U.K. and Australia, private insurance coexists very well with government insurance plans.) A debate between those two sides would be clarifying and healthy for the party.

But tacking on single payer as just another item in your to-do list? It’s a little bit much to swallow.