An earlier version of this story conflated Democrats’ health care plans regarding single-payer and universal coverage.

The progressive wing of the Democratic Party is attempting to wrest power away from moderates and establishment liberals -- and nudging the party leftward on a host of issues, especially health care. This dynamic is not taking place only in New York City where self-proclaimed socialist Alexandria Ocasio-Cortez handily defeated 10-term incumbent Rep. Joe Crowley.

In swing districts across the country, Democratic congressional candidates have embraced Bernie Sanders’ single-payer health care plan or are pushing an expanded version of Obamacare while promising universal coverage.

In an analysis of RealClearPolitics’ tossup list of contested House seats, it’s clear that the progressives’ approach to health care is catching fire even in the nation’s heartland. Out of 24 swing-district Democratic candidates who’ve gotten through the primary process, 17 of them, 70 percent, support Medicare for All or an expansion of the Affordable Care Act that would eventually provide universal coverage to everyone in the country.

Jason Crow, who is challenging Colorado Republican Rep. Mike Coffman, is among those Democrats who believe this is a winning issue. “Health care is a right, not a privilege,” he states on his campaign website. “We must not only protect hard-won gains under the ACA, but also work towards universal health care.” While making it clear that he doesn’t advocate undermining employer-based health insurance, Crow also says he will “fight for a public option” as well.

Anthony Brindisi, a Democrat (pictured) running in upstate New York against incumbent Republican Rep. Claudia Tenney, has reminded audiences that in the Legislature he backed the New York Health Act, a single-payer system. “I want to see a system where everybody can have health insurance in the country,” he’s said on the 2018 campaign trail. “Whether we call it single payer or Medicare for All, there’s lots of different ideas out there.”

Illinois Rep. Peter Roskam’s Democratic opponent proclaims on his website: “The Affordable Care Act (a.k.a. Obamacare) took a big step towards universal healthcare in the U.S.” Southern California Democrat Katie Hill, running against Rep. Steve Knight, says she’s “ready to take immediate steps to provide health care relief for the people who need it by strengthening the ACA and laying the foundation for a Medicare for All system.”

After Republicans failed to repeal or replace the Affordable Care Act, the energized progressive movement seized the opportunity to push single-payer government-run health care in the midterms. “Single-payer” has never poll-tested well, partly because Republicans have branded this approach “socialized medicine.” So progressives decided to repackage the single-payer concept into a more appealing-sounding “Medicare for All.” In 2017, Sanders relaunched his proposal with 16 other senators, four of whom are potential 2020 presidential candidates. A similar bill with more than 100 co-sponsors has been introduced in the House. This past week, a group of Democratic House members formed a Medicare for All Caucus to support their push to change the health care system.

Medicare for All offers a utopian vision: effective, cheap, and high-quality insurance coverage for all Americans that also lowers both costs and – somehow -- the federal budget deficit. Unsurprisingly, voters in polls respond favorably to the promise of free and improved health care.

“I support the goal of getting the profit motive out of our health care system,” said Antonio Delgado, who is running against New York Republican John Faso. His goal, he added, “is to get us to universal coverage as fast as possible.”

Despite the savvy marketing and growing buzz around Medicare for All, there’s little discussion from progressives about how to finance the plan or cover the costs. An independent review of the Medicare for All plan put the cost at $32 trillion over 10 years, according to the left-leaning Urban Institute. Even when Bernie Sanders released his updated plan, he avoided including a cost estimate, instead providing a “white paper” with financing options. Without providing specific numbers, Sanders proposes funding his plan through a vague combination of taxes on the wealthy, estates, capital gains, and stock transactions. Conservatives maintain that even these tax increases would fall short of the needed revenue to cover the costs. “It would break Medicare,” said House Majority Leader Kevin McCarthy. “And it would end any private insurance as we know it.”

Progressives disagree. “Medicare for All will be cheaper and it will not reduce health care,” said Democrat Scott Wallace, who is running against Republican Brian Fitzpatrick in suburban Philadelphia. He added that his plan will “create a hybrid system that will cover everybody and at a lower cost.” Democrats point to the successes of European centralized health care plans as proof that the concept is feasible and that Republican prophecies of financial doom are overblown.

Medicare for All is becoming a classic wedge issue for both parties. It allows Republicans to accuse Democrats of being fiscally irresponsible, wanting to raise taxes, and scheming to further reduces the choices Americans have over what doctors, specialists, and hospitals to use. Meanwhile, it affords Democrats the opportunity to paint Republicans as callously indifferent to the medical needs of working-class families.

On one issue, the Democrats have an undeniable point, however: Despite controlling the House, Senate, and White House, Republicans have not put forward a coherent message or unified plan after failure to repeal or replace the ACA. When House Speaker Paul Ryan was asked about the next steps, he said the GOP is “going back at incremental health-care reform and other entitlement reforms so we can chip away at this problem.” He added, “I think the best chance we have is going after incremental entitlement reform.”

Despite internal policy squabbles, Democrats are united in their anger at a decade of legislative stalemate and partisan conflict. “These legislative failures show what is wrong with the status quo in Washington,” said Rep. Conor Lamb, a conservative Democrat who won an upset special election in a Republican district. He added: “Republican leaders have not even allowed a vote on a bipartisan, common-sense effort to strengthen the ACA and stabilize the markets.”