Democrats who are giddily munching popcorn while watching Republicans struggle with trying to repeal Obamacare may want to put down the tub. They are on the verge of adopting a politically analogous health care plank, one designed to rev up their ideological base in the next campaign, but destined to make the party suffer once in power.

Last week, Elizabeth Warren, the Massachusetts senator and possible presidential aspirant, declared in a Wall Street Journal interview that after stymying repeal, the “next step” for Democrats should be “single-payer” -- a health insurance system with only one main insurer run by the federal government. This is a shift for Warren; she had refused to back single-payer in her 2012 Senate run. And it has seismic repercussions for the Democratic Party.

Previously, only gadfly Democratic presidential candidates touted single-payer: Jerry Brown in 1992, Dennis Kucinich in 2004 and 2008 and Bernie Sanders in 2016. But Sanders graduated from gadfly to heavyweight contender, and in turn, intensity on the left for single-payer has grown. This year, for the first time, the perennial “Medicare for All” bill is being co-sponsored by a majority of the House Democratic Caucus. One health policy expert recently told Vox, “Democratic politicians I never thought would utter the words have mentioned single-payer to me in a non-joking way of late.”

You can now expect other 2020 presidential candidates to wave the single-payer banner. (A few days after Warren's move, another possible candidate, Sen. Kirsten Gillibrand, followed suit.) No longer can Democrats breezily wave off Iowa and New Hampshire health-care activists with pragmatic rationalizations. Democrats will have to either embrace single-payer to avoid being tagged as ideologically timid or soullessly corporatist, or engage in politically risky trench warfare with the party’s left wing. If Warren is on the debate stage, perhaps alongside Sanders, any rejection of single-payer will be particularly glaring.

This is the part of the reasoned pundit’s analysis where I’m supposed to say that the Democrats are going too far to the left to win in the general election. But one can’t assume that to be true.

Spend five minutes with a committed Berniecrat and you will learn that poll after poll shows majority support for single-payer. The claim is oversimplified; poll numbers range widely depending on how the question is worded, and support drops when faced with the prospect of “large increases in government spending.” Nevertheless, polls on issues don’t necessarily determine who wins elections. Most voters didn’t want to fully repeal Obamacare, yet we elected a man who pledged to do just that. Middle-of-the-road voters may not be completely sold on single-payer, but we can’t know if it would be an Election Day deal breaker.

The big danger single-payer presents Democrats wouldn’t necessarily manifest on Election Day, but afterwards.

Today’s Republicans are in a pickle because they spent seven years ginning up their base with cries of “Repeal!” without putting sufficient thought into replacement. “Nobody knew that health care could be so complicated,” whined President Trump, who obviously paid little attention to the legislative process that produced the Affordable Care Act.

Initially, Republican legislative leaders planned to buy themselves time, and discussed putting off a replacement for as much as three years. But because the conservative base had been whipped into such a frenzy, the leaders concluded they had to forge ahead, torpedoes be damned. The result has been slapdash legislation blown to bits by torpedoes from the Congressional Budget Office. Either a faction of Republicans will break ranks and kill the bill, risking charges of betrayal from conservative die-hards, or the bill will actually become law, risking anger from the millions of voters likely to be saddled with higher health care costs.

If Democrats take back Congress and the White House on a pledge to enact single-payer, they would find themselves in a similar predicament. While expectations of the progressive base would run high, the simplistic talking points of the campaign would run smack into the realities of health-care policy.

Democrats would not be able to quickly ram through the existing House “Medicare for All” legislation, which is a wisp-thin, not-ready-for-prime-time 30 pages long. And digging into the details would not be pretty.

Already we’ve seen single-payer pushes founder in deep blue Vermont and California because the upfront costs were steep and few were willing to support the necessary tax increases. The controversial line that greased passage of the Affordable Care Act – “If you like your health care plan, you can keep it” – would be non-operative in a single-payer debate; people currently satisfied with their health insurance would instead be told they would have to give it up for a government plan. The insurance industry would be literally fighting for its life, and would spend millions stoking every possible concern anyone could have about a wholesale revision of one-sixth of the United States economy.

Could a progressive populist revolution overcome these challenges? One can never say never. But anyone who saw what Barack Obama’s Democrats had to go through to barely squeeze the Affordable Care Act through a heavily Democratic Congress (including the subsequent loss of the House) or saw how “HillaryCare” was destroyed in 1994 by the insurance lobby’s “Harry and Louise” ad campaign, has to be deeply skeptical. Any health reform proposal involves trade-offs that make some people unhappy. At minimum, the process would be a bitterly fought slog.

Which raises the question: Why would progressive activists effectively force the Democratic Party to commit to single-payer when there are so many other pressing issues? Democrats already paid a stiff political price to win a massive expansion in health insurance coverage with a program that can still be refined over time. Why bet the house (and the Senate) on a sequel, when there is plenty to do on jobs, wages, climate, immigration and civil rights?

“The mover on health care loses. To do something is to lose,” warned battle-scarred Democratic operative James Carville earlier this year. Republicans failed to heed his warning. Democrats, who have repeatedly gone through the health care wringer, shouldn’t need a reminder.