While speaking at a candidate forum Monday in Washington, D.C., Joe Biden appeared to give the audience a little sneak peek of his health care plan:

Biden answer on health care that sounded new, at least to me: "I think everyone’s entitled to have total health care, and what I would do is make sure that every single person in the United States has access to Medicaid right off the bat." — Dave Weigel (@daveweigel) June 17, 2019

Universal access to Medicaid? Tantalizing! But also vague. The one-liner could have hinted at anything from a massive expansion of government insurance to a more modest public option along the lines of what Minnesota Sen. Amy Klobuchar has backed. When I asked for clarification from Biden’s presidential campaign, it emailed the following statement:

The Biden health care plan will include access to a Medicare-like public option for anyone who wants it. It will also include premium-free access to this public option for people who would otherwise qualify for Medicaid but have been denied access to it by governors and state legislatures who have refused the Affordable Care Act’s Medicaid expansion.

So, that’s not really universal Medicaid, and it’s still vague. But it gives us something to work with.

Biden’s team is describing a bill that, at the very least, would make Obamacare work more like its architects and supporters originally envisioned. It would create a public insurance option open to all—something that progressives tried and failed to include in the law back in 2010—and make it a zero-premium option for Americans who were shut out of the Medicaid expansion after the Supreme Court essentially ruled that states could opt out of it.

That might not sound like much to a die-hard Medicare-for-All supporter. But it’s more ambitious than some of the ideas to expand health coverage making the rounds on Capitol Hill these days, such as the rather limp plan to let Americans between the ages of 50 and 64 buy into Medicare that a group of moderate Democrats trotted out. Depending on the details, it’s potentially more far-reaching than Sen. Brian Schatz’s bill to create a public option through Medicaid, which would would leave much of the decision making to the states.

But the details are important. And on that front, Biden’s little squib of a statement of obviously raises a lot more questions than it answers.

For instance:

• What does “Medicare-like” mean?

• What will the copays be for middle-class enrollees?

• What will the deductibles be?

• Will poorer Americans, who’d otherwise be entitled to nearly free health care through Medicaid, get a break on out-of-pocket costs?

• What will this plan pay doctors and hospitals?

• Will it try to use the government’s power to reduce health care costs by pegging payments to Medicare rates?

•Will businesses be allowed to buy this plan for their employees?

The plan Biden’s team describes also sounds like it could create some unintended consequences. For one, it might reward states that chose not to expand Medicaid by having the federal government pay the entire cost of insuring their lower-income residents. (Biden could try to make states pick up some of the tab, but that might not be constitutional). Would other states that did choose to expanded Medicaid roll back their programs and dump their residents into the federal health care plan? It seems like a possibility—and not necessarily a bad thing, if your goal is to federalize U.S. health-care spending through the back door. But if that’s your goal, then it raises yet another question:

• Why not just create a single federal program for people currently eligible for the Medicaid expansion, rather than a patchwork of options that vary depending on whether they live in a red state or blue state? Why not keep things simple?

Anyway, I’ve forwarded most of these questions on the Biden campaign. No response yet. Hopefully they’ll start coloring in their outlines sometime soon.