If I asked 100 of you what the most important moment from last week’s debates was, I’m sure that 99 of you would say it was Kamala Harris’ strike at Joe Biden. Obvious, right?

Maybe in the short term. In the long term, though, there’s good reason to think it might rank no higher than third.

What then was the first most important? Elizabeth Warren and Kamala Harris raising their hands to affirm they’d eliminate private insurance. And second? All 10 combatants on the second night agreeing that they would push for health coverage for undocumented immigrants.

That amounts to taking away health-care coverage from many millions of people and at the same time giving coverage to a few million who entered the country illegally. This is a potential political disaster. Having just won a historic victory in the 2018 election on health care, the Democrats now seem hellbent on trying to lose the 2020 election on the same issue.

Let’s start with the first matter. As you saw, on night one, Lester Holt asked the candidates for a show of hands on which among them would “abolish their private health insurance in favor of a government-run plan?” Warren and Bill De Blasio raised their hands. The second night, Holt asked the same question, identically phrased. Harris and Bernie Sanders were the only two to raise their hands.

Harris, sensing the reality I’m writing about here, started trying to walk it back the next day. She claimed to have misunderstood the question, that Holt was asking about her own personal health-care coverage. This seems hard to believe, but whatever; she said on Morning Joe that no, she would not in fact eliminate private insurance. Warren has made no such gesture as of this writing.

I hope she does, and soon, because this position is political suicide. About 150 million Americans, or roughly two-thirds of all insured people, have private-sector insurance. And contrary to what a lot of Medicare for All backers say, the vast majority of people rate their own coverage as excellent or good.

So the Democrats are really going to campaign on eliminating that in one fell swoop? It’s way over the top. Even Medicare as it exists now doesn’t eliminate private insurance, as about one in four Medicare recipients supplements their coverage with a private plan. So Medicare for All, if it wanted to be true to its name, would allow everyone to do that.

We already know the Trump-GOP talking points here: “OK, so let me get this straight. The Democrats want to do away with private insurance. And they want to replace it with a big, government-run system that will be brought to you by the same party that oversaw the Obamacare rollout. Oh, and by the way, while creating this mayhem, they’re going to raise your taxes by $10,000 or $15,000.”

The even scarier attack line will concern hospitals, since the lower reimbursement rates to hospitals under Medicare will mean that many hospitals would face financial crises and might close. How do you think that will play in swing House districts, where 30-odd Democrats will be struggling to hold onto their seats, being forced to defend this position if someone who holds it wins the nomination? And on top of that, there’s the question of the millions of people who work in the private-insurance business. Unemployment could spike in hundreds of decent-sized towns in the country, local economies noticeably disrupted.

Republicans and conservative dark-money groups would work the country into a state of mortal panic by Election Day if eliminating private insurance were the Democratic position. And imagine compounding that by at the same time offering coverage to undocumented immigrants.

Of course, people must be treated humanely. And yes, there is a public health argument for providing such coverage—disease doesn’t know who holds a green card and who doesn’t, and so providing health care to people who live here is defensible from a common-good point of view. And finally there is a financial argument—denying people preventive care services just means they’ll rely on later and more expensive emergency care.

All that is true, and if we lived in a rational world, we could discuss this rationally and come up with a compromise policy that made sense. Some municipalities do provide some coverage to undocumented people, and California just passed a law that will extend Medi-Cal coverage to undocumented children. Talking about expanding that nationally might be a position that could fly, since it concerns children.

But California ain’t America, and we don’t live in that rational world. We live in a world where a racist demagogue who basically got elected by fearmongering about undocumented people sits in the Oval Office. And he watched the debate—the second night, which was the only night the question came up—and started licking his chops. He immediately tweeted: “All Democrats just raised their hands for giving millions of illegal aliens unlimited healthcare. How about taking care of American Citizens first!? That’s the end of that race!”

I’m obviously not saying that Republicans have a moral leg to stand on in either of these matters. They do not. Trump keeps saying they’re going to come up something great and beautiful, but he doesn’t know what he’s talking about, and Mitch McConnell and the rest of the congressional GOP don’t want to do anything on health care except take it away from people, and dismantle Barack Obama’s legacy just for the sake of dismantling it. And all they want to do for undocumented people is send them home after separating them from their children.

I’m just talking about raw politics in the context of a presidential campaign (and, let’s not forget, a simultaneous congressional campaign in which it’s imperative that Democrats keep their House majority, which means they need to hold the swing districts they carried last time). And in raw political terms, these positions stand to lose the Democrats votes. Lots of votes.

There’s plenty of time to wriggle away from these positions, as Harris is doing. Health care was the Democrats’ best topic in 2018. It should be their best topic again. Let’s hope they don’t make it their worst.