Sen. Elizabeth Warren (D-Mass.) during the Democratic primary debate in Miami on Wednesday. (Wilfredo Lee/AP)
Opinion writer

Sen. Elizabeth Warren (D-Mass.) dealt with a short-term problem Wednesday night — the threat from Sen. Bernie Sanders (I-Vt.). But she might have created a much bigger long-term problem for herself.

Back in March at a CNN town hall, she said, “When we talk about Medicare-for-all, there are a lot of different pathways. What we’re all looking for is the lowest-cost way to make sure everybody gets covered.” She then ran through ways to do that — lowering the age for Medicare, expanding Medicaid. She added: “For me what’s key is we get everybody at the table on this. … But what’s really important to me about this is we never lose sight of what the center is. Because the center is about making sure that every single person in this country gets the coverage they need and that it’s at a price that they can afford.” That’s a pretty good answer that doesn’t give Republicans a club with which to hit her over the head (“Socialism!” “Take away your health care!”) in the general election.

Then came Wednesday night: With only New York Mayor Bill de Blasio in agreement (which should tell her something), Warren emphatically called for eliminating all private insurance:

Look at the business model of an insurance company. It’s to bring in as many dollars as they can in premiums and to pay out as few dollars as possible for your health care. That leaves families with rising premiums, rising copays, and fighting with insurance companies to try to get the health care that their doctors say that they and their children need. Medicare for all solves that problem.

And I understand. There are a lot of politicians who say, oh, it’s just not possible, we just can’t do it, have a lot of political reasons for this. What they’re really telling you is they just won’t fight for it. Well, health care is a basic human right, and I will fight for basic human rights.

You can hear Republicans giggling in the background. If she is the nominee, they get to talk about her taking away your doctor and health-care plan and about how rural hospitals will close (due to low reimbursement rates). Doubling down on a plan easily characterized as creeping “socialism,” which turns out to be not so popular, seems unwise. (And as we have pointed out, when people are told that Medicare-for-all would outlaw private insurance, support for the idea plunges.) As Jonathan Chait put it, “Warren ventured boldly, perhaps foolishly, onto a shaky limb. She may have just filmed the most effective attack ad against herself.”

Who Republicans don’t want to face is a candidate like Sen. Amy Klobuchar (D-Minn.) who said, “I think we share the goal of universal health care. And the idea I put out there, the public option, … is that you use Medicare or Medicaid without any insurance companies involved, you can do it either way. And the estimates are 13 million people would see a reduction in their premiums, 12 more million people would get covered.” She added, “So I think it is a beginning and the way you start and the way you move to universal health care.”

With slightly different emphasis, Sen. Cory Booker (D-N.J.) took this view: “Health care — it’s not just a human right, it should be an American right. And I believe the best way to get there is Medicare-for-all. But I have an urgency about this. When I am president of the United States, I’m not going to wait. We have to do the things immediately that are going to provide better care.” That was where Warren seemed to be before she doubled down on Medicare-for-all Wednesday night.

The truth is Warren was already passing Sanders in polls and was becoming a “compromise” candidate for the most progressive wing and for moderates. Now, moderates might see her as pretty much in the same boat — with the same electability worries — as Sanders.

When Sanders inevitably touts his Medicare-for-all plan Thursday, his more moderate opponents might point out that even on Wednesday’s Democratic debate stage, only 20 percent of the candidates favored outlawing private insurance and that, just like his “free college for everyone” plan, Sanders is asking working class people to pay taxes so rich people don’t have to pay for health care. They might note that unions have given up years of wage increases to get really good health-care plans that Sanders would snatch away.

Maybe Warren’s unqualified embrace of Medicare-for-all won’t hurt her a bit, but I would caution Democrats: The one sure way to lose in 2020 is to allow President Trump to paint Democrats as crazy socialists who want to take away things voters like (their health care, their SUVs, etc.). Why Democrats, who say beating Trump is the absolute most important thing, would take that risk is a mystery.

Read more:

Jennifer Rubin: The first debate: Who won, who lost and what matters

Henry Olsen: Elizabeth Warren throws red meat to her base

Elizabeth Bruenig: So, what’s the difference between Warren and Sanders?

E.J. Dionne Jr.: The first debate showed Democrats are far more in consensus than at odds

Ed Rogers: Ranking the Democrats’ debate performances

Jennifer Rubin: What Thursday’s debaters should learn from Wednesday night