Elizabeth Warren has always been the best self-described Democrat in the presidential primary race. Apart from independent Bernie Sanders, she’s the only other candidate whose politics contain an inkling of class war and espouses an even remotely credible disdain for the financial sector.

But as she has cozied up to the Democratic establishment as her poll numbers have surged, it’s been unsettling to watch the case for Warren creep from “Wall Street Fears Her” to the more technocratic “She’s Got a Plan for That” — particularly since her pantheon of plans has largely snubbed health care.

That changed this week: at long last, Warren’s campaign website includes a health care section, which declares her support for Medicare for All. She’s also used the phrase more often in debates and interviews.

But when it comes to specifics, her messaging has remained frustratingly murky — leaving just enough wiggle room for plausible deniability about what exactly her political vision is.

“Medicare for All” has always been an imperfect slogan. It’s the official name of bills in the Senate and House — sponsored by Sanders and Rep. Pramila Jayapal, respectively — outlining a single-payer health care system in which all health care costs are paid by the government rather than by a patchwork of public and private insurers. They envision health care provided free at the point of use, financed not according to health status through copays and deductibles, but by ability to pay, through progressive taxation.

But the single-payer movement has always had a branding problem: health care policy is tedious, and it’s not intuitively obvious what “single payer” means, or why one payer would be more equitable and efficient than multiple payers. “Medicare for All” is essentially a way to quickly describe the concept to an American audience, for whom the federal Medicare program is a familiar referent. The robust single-payer system conceptualized in Sanders’s and Jayapal’s bills goes much further than existing Medicare, which includes significant cost-sharing and large roles for private insurers. But that’s too much to squeeze onto a campaign button.

As a slogan, “Medicare for All” has proven to be popular but porous: it polls differently depending on how questions are phrased or what elements of the plan are emphasized, and has also been widely co-opted. Candidates like Kirsten Gillibrand and Kamala Harris have both claimed to support “Medicare for All,” only to clarify later they meant something akin to an optional buy-in to a Medicare-esque program. The Center for American Progress’s “Medicare Extra,” eventually put into bill form under the title “Medicare for America,” likewise draws on the popularity of “Medicare for All” while describing a significantly watered-down version of what Sanders and Jayapal mean by the phrase.

The differences between these frameworks are substantial, yet Warren’s messaging has been just vague enough to refer to any of them. “Elizabeth won’t stop fighting until everyone is covered and no one goes broke paying a medical bill or filling a prescription,” her website now reads. Both things are absolutely true under Medicare for All. But universal coverage isn’t unique to single payer, and there’s a wide gulf between no one going broke and eliminating cost-sharing.

Later, the site reads: “Elizabeth supports Medicare for All, which would provide all Americans with a public health care program. Medicare for All is the best way to give every single person in this country a guarantee of high-quality health care . . .  No more fighting with insurance companies.” That would seem to be clearer, but still indicates nothing about whether people would be automatically absorbed by the new program, whether currently existing public insurers would be, whether it’s supported by premiums, taxes, deductibles, or copays, or how central a role private insurers would play in the health care system, whether or not patients fight with them. Nor does her updated website point to the Medicare for All bill she cosponsored in the Senate, which addresses all of these questions.

Those gaps are wide enough that the bulk of the plan’s political content fits inside of them. Americans are already paying for health care through a combination of premiums, taxes, and out-of-pocket costs, which will remain true under any health care financing system. While single payer shifts costs entirely into taxes, plans that maintain cost-sharing redistribute those costs more heavily onto people with greater care needs — disproportionately sicker and poorer people and women.

As long as there’s cost-sharing, there will be a cost-barrier, replicating the same market dynamics that block so many people from accessing care today. Similarly, the role maintained for private insurers says much about the vision overall: a system based around for-profit gatekeepers — even when patients “choose” to keep their plans — will involve fighting with insurers by definition. Happily paying every claim no matter what is antithetical to their business model.

Obviously, no one is under any illusions that a single-payer bill — or even anything falling significantly short of it — could possibly be passed right now. Doing so will require an amenable chief executive and congressional majority, a willingness to break procedural norms at the national level, and a mass movement exacting pressure at all points of the process.

But nailing down candidates’ visions for a just health care system is still important regardless of current institutional constraints: it’s the only way to gauge how a president is most likely to spend political capital, what they’ll trade off, and which hills they’ll die on. It’s the only way to know how they’ll deploy the power of their base, what they’re willing to be hated for, and what constituencies they’re the least likely to piss off.

It’s obvious how Bernie Sanders would answer these questions. We’re still waiting on Elizabeth Warren.