Emotional testimony at first congressional hearing on Medicare-for-all proposal Republicans have seized on Democrats' health care debate ahead of the primary.

Lawmakers heard emotional testimony at the first congressional hearing on Medicare-for-all legislation on Tuesday, as the progressive pitch to reshape American health care dominates policy discussions in the 2020 Democratic presidential primary.

The House Rules Committee hearing focused on legislation from Reps. Pramila Jayapal, D-Wash., and Debbie Dingell, D-Mich., co-sponsored by more than 100 Democrats and building on ideas promoted most prominently by presidential candidate Sen. Bernie Sanders.

The House Democrats' proposal would not require patients to pay for any expenses and would include primary, hospital, dental, vision and maternity care. It would cover prescription drug costs and allow the government to negotiate drug prices directly with manufacturers.

A 35-year-old progressive activist, Ady Barkan, in a wheelchair and unable to speak without the help of a computer program, captivated lawmakers as he called on Congress to approve Medicare-for-all legislation.

"Never before have I given a speech without my natural voice and needed a computer synthesizer," he said.

While he has private health insurance coverage, Barkan described how is family is forced to pay $9,000 per month for around-the-clock nursing care at home because of his ALS, which he was diagnosed with three years ago.

"We have so little time left together, and yet our system forces us to waste it dealing with bills and bureaucracy," he said of his family. "That is why I am here today, urging you to build a more rational, fair, efficient, and effective system. I am here today to urge you to enact Medicare-for-all."

Democrats and Republicans used the first congressional hearing on Medicare-for-all to sharpen their political arguments over the progressive proposal.

"I believe health care is a right for all, not a privilege for the lucky few," chairman Jim McGovern, D-Mass., a co-sponsor of the House bill, said Tuesday. "This Congress is putting that belief into action."

"The ACA changed lives. It saved lives. But we knew then it was never going to be the last stop in health care reform, that we were always going to have to come back and build upon those core values. And that's what today is all about."

Rep. Tom Cole of Oklahoma, the top Republican on the committee, warned that the proposal would outlaw private insurance, and tried to tie the plan to President Barack Obama's infamous promise about the Affordable Care Act.

"Even if you like your plan, you really can't keep it," Cole warned.

"This bill is a socialist proposal that threatens freedom of choice and would allow Washington to pose one-size-fits-all plans on the American people," Cole said.

Republicans continued to push political buttons outside the hearing.

Reps. Kevin Brady, R-Texas, and Devin Nunes, R-Calif., top Republicans on the House Ways and Means Committee, have requested a hearing on Medicare-for-All from Chairman Richard Neal.

"This is a fantasy pulled from the farthest corners of the left," Senate Majority Leader Mitch McConnell said on the Senate floor Tuesday.

Republicans also repeatedly seized on the disruptive impact it would have on the health insurance of tens of millions of Americans.

Witnesses across the political spectrum acknowledged the enormous price tag associated with the undertaking of implementing Medicare-for-All, a point repeatedly raised by Republicans.

Republicans and witnesses also warned against limiting choices for consumers by limiting private health insurance.

"In a country that values diversity, will one program with one list of benefits and set of rules work for everyone?" Grace-Marie Turner, the president of the Galen Institute, asked in her opening remarks.

The Democrats' bill, which does not include a funding mechanism, also would preserve health care and medical benefits from the Veterans Administration and Indian Health Service, and give consumers two years to phase in to the program.

Sanders' latest proposal for a single, national health insurance program would give Americans four years to join, instead of two, and handles some long-term care differently. It would also allow for co-pays for prescription drugs capped at $200 annually.

After Democrats' successful midterm campaigns zeroed in on pre-existing conditions coverage, Republicans on Capitol Hill have seized on the other party's health care debate ahead of 2020, using procedural votes and committee meetings to highlight questions about Medicare for all's cost and potential impact on private health insurance.

"Patients and families want more choice and control over their doctors, treatments and coverage. They want lower costs and greater access to care. But government run, one-size-fits-all health care is not the answer," Rep. Greg Walden, R-Ore., the top Republican on the House Energy and Commerce Committee, said in a statement to ABC News. "The Democrat plan is socialism. Under their plan, Americans will have fewer choices, taxes would skyrocket, and access to care would slow to a crawl."

In February, Walden requested a Medicare-for-All hearing in the Energy and Commerce Committee, in an effort to highlight questions about the cost of the proposal.

The Mercatus Center at George Mason University estimated last year that Sanders' plan would cost more than $32 trillion over ten years. Sanders has argued that the federal government is already spending significant sums on health care and could redirect some current spending to the new program, in addition to raising taxes on "extreme wealth."

Democratic leaders said Tuesday's hearing would be the first of several in the House on Medicare-for-all legislation. The House Budget Committee will hold a hearing in May on a forthcoming analysis from the nonpartisan Congressional Budget Office of single-payer health care, according to a spokesperson.

The tax-writing Ways and Means Committee, along with the Energy and Commerce Committee, with its jurisdiction over health policy, could also take up the topic later this year.

"The fact that it’s not in the ultimate, top committee that you might have to go to, is just one piece of it," said Jayapal, who pointed out that she negotiated to hold the first hearing in the Rules Committee. "We want to talk about this and get the ideas out, and have people understand what’s really in the bill."

"Anything we do to move the debate forward is positive," Rep. Mark Pocan, D-Wis., a leader of the Congressional Progressive Caucus and co-sponsor of the Medicare-for-All Act of 2019, told ABC News.

The hearing also energized activists: More than 400 nurses stormed the nation's capital Monday ahead of the hearings in support of the legislation.

National Nurses United, the largest union of registered nurses with more than 150,000 members nationwide, has been an avid promoter and supporter of the legislation for years. The group also campaigned heavily for Sanders during 2016.

On Monday, the nurses protested in front of the Pharmaceutical Research and Manufacturers of America headquarters and lobbied at House Speaker Nancy Pelosi's office.

The group has grassroots organizing, canvassing and phone-banking events planned around the country in the coming months and, according to the union, its leaders plan to attend the hearings Tuesday to share stories about "patients suffering because of difficulties of the current health care system."

"My concern is that more incremental solutions may be advanced and may sound attractive, but if implemented wouldn't solve the fundamental dysfunctions and injustices of the American health care system," Dr. Adam Gaffney, the president of Physicians for a National Health Program, a 20,000 member single-payer advocacy group, told ABC News.

Gaffney, a critical care doctor and instructor at Harvard Medical School, said he's worried Democrats could "veer away from policy towards political expediency."

"This," he added, "is obviously the beginning of a process, not the end. I'm less concerned with where we start then where we finish up."