Liberal Democrats’ ambitious plan to transfer Americans to a government-run “Medicare-for-all” system took a step forward Tuesday as the House held an emotional first hearing for the proposal -- and Republicans vigorously pushed back, warning the program would offer inferior health care at tremendous cost.

The Rules Committee hearing was held to look at the 2019 Medicare-for-All Act, introduced by Reps. Pramila Jayapal, D-Wash., and Debbie Dingell, D-Mich., and co-sponsored by more than 100 House Democrats.

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Presidential candidates Pete Buttigieg, Cory Booker, Kamala Harris, Kirsten Gillibrand, Bernie Sanders and Elizabeth Warren have all endorsed some version of the proposal, bringing the plan from the party's fringes into the Democratic mainstream as the 2020 election nears.

The hearing was an emotional one, particularly during the testimony of activist Ady Barkan, who was diagnosed with ALS in 2016 and testified about his struggles with the health care industry in getting coverage for treatment for his condition.

Supporters seated near him wiped tears from their eyes as he spoke of becoming increasingly paralyzed from the condition. He testified via a computer system that tracks his eye movement and converts text into speech.

“This health care system only works if you’re a pharmaceutical or health care industry executive who wants to maximize their own profit at the expense of people like me,” he said. “It is simply unconscionable that I should have to pay $9,000 a month for lifesaving medical care at a time when the insurance industry is raking in record profit.”

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“That’s wrong and it needs to stop,” he said.

Despite warnings that most "Medicare-for-all" plans would largely abolish private insurance, Democrats downplayed the claim from opponents that it would have negative effects on Americans.

“People aren’t going to lose their health care with Medicare-for-all, you’d actually get to keep your doctors, and go to your hospitals that you currently have -- the only difference is that you wouldn’t have to deal with insurance companies,” Chairman Jim McGovern, D-Mass., said.

But Republicans disagreed, arguing that it would lead to worse care and less choice.

“Medicare-for-All would require all Americans to pay more in taxes, wait longer for care and receive potentially worse care, even worse it would put our existing Medicare recipients at risk,” Rep. Tom Cole, R-Okla., said

Republicans called on witnesses who warned that abolishing private health care for a government-run system would be costly (some estimates have put the cost as high as $32 trillion, though some of that would offset what Americans already spend on premiums and deductibles) and lead to less choice.

“It is hard to see how consumers would be more empowered when dealing with a single government payer in a country that values diversity,” Galen Institute’s Grace Marie-Turner testified. ”Will one massive program, with one list of benefits and one set of rules work for everyone?”

Republicans and allied groups have pushed back heavily on Medicare-for-all, suggesting it is the latest example of the Democratic Party lurching left and embracing socialist ideas.

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“This is just the latest evidence that Democrats in Congress are being rapidly consumed by socialism. ‘Medicare for All’ is socialism by any other name. It’s a government takeover of private health insurance, which over 200 million Americans rely on, including 38 million small business employees. The financial cost, estimated at $33 trillion, would cripple our economy and probably throw us into recession,” Alfredo Ortiz, CEO of the Job Creators Network, said in a statement.

“Now is the time for reasonable Democrats to speak out and push back against ‘Medicare for All.’ Americans deserve a real healthcare debate, not just failed ideas and cheap slogans,” he said.

The hearing comes amid lukewarm support for the policy from Democratic leadership. House Speaker Nancy Pelosi, D-Calif., has been publicly skeptical about Medicare-for-all and Politico reported this month that one of her advisers, Wendell Primus, urged health care policy groups to raise their concerns about the plan.

Pelosi said in February that Medicare-for-all would not be “as good a benefit as the Affordable Care Act.”

“It doesn’t have catastrophic [coverage] -- you have to go buy it. It doesn’t have dental. It’s not as good as the plans that you can buy under the Affordable Care Act. So I say to them, come in with your ideas, but understand that we’re either gonna have to improve Medicare -- for all, including seniors -- or else people are not gonna get what they think they’re gonna get,” she said in an interview with Rolling Stone. “And by the way, how’s it gonna be paid for?”

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The response has led to concerns from progressives that the hearing would amount to little more than "deliberation theater," charging that Primus was involved in planning the hearing.

But congressional Democrats have strongly pushed back on those claims, saying only the Rules Committee -- not the speaker's office or anyone else in the Democratic Party leadership -- has the final say over the proceedings, and that the hearing is designed to quickly but thoroughly consider the proposal.

Fox News' Gregg Re contributed to this report.