Speaker Nancy Pelosi is guiding House Democrats along a narrow path as she seeks to convince party progressives that the idea of providing Medicare for everyone in the U.S. is being taken seriously, while assuring moderates that the House won’t move too far, too fast.

The House on Tuesday will gavel in the first-ever hearing on a sweeping Medicare for All proposal, an idea that’s energized the Democratic left, which is pushing to make it a central part of the 2020 campaigns for the White House and Congress.

If private health insurers are one day put out of business by a government-run single payer health system, they may look back at Tuesday as the beginning of the end. Yet the bill coming before the House Rules Committee won’t become law anytime soon and may never get a hearing in the committees that oversee Medicare.

Rep. Pramila Jayapal of Washington state, sponsor of the legislation and a leader of the Democrats’ progressive faction in the House, said she’s playing the long game.

“This is first step but certainly not the last step,” she said in an interview. “There is tremendous amount of attention coming to this issue because of the presidential candidates.”

Sen. Bernie Sanders of Vermont, one of the leading contenders for the 2020 Democratic nomination, has introduced his own Medicare for All bill in the Senate. Four of his Senate colleagues also seeking the Democratic nod, Kamala Harris, Cory Booker, Kirsten Gillibrand and Elizabeth Warren, have signed on as co-sponsors.

But some of the other candidates have stopped short of endorsing the replacement of private insurance plans with the government’s Medicare program, which now covers those 65 and older. Former Vice President Joe Biden, Sanders’ main competitor at this stage of the campaign, on Monday said he supported giving Americans an option to buy into a Medicare-based insurance plan.

In the House, Jayapal’s bill has backing from 109 out of 235 House Democrats.

“From my read of the room, there isn’t support for that proposal,” said Rep. Ben McAdams, a freshman Democrat who represents a swing district in solidly Republican Utah. “I’m worried it causes more problems than it solves.”

Pelosi and other House leaders are moving cautiously. They are promoting a bill to shore up Obamacare and developing legislation to lower drug prices, while letting the debate on a more radical overhaul of the health system continue. The two committees with jurisdiction over Medicare haven’t agreed to hold hearings and there is no push for a floor vote this year under discussion.

“Things are moving at a faster pace than some had anticipated and I think that’s good,” said Massachusetts Rep. Jim McGovern, the Rules Committee chairman and a supporter of the Medicare for All bill. “This is not being slow-walked, we are trying to ignite the discussion on this.”

Some Democrats have said they prefer lowering the Medicare age to 55, allowing people to buy into the program or a public option to compete with traditional insurance. A group of liberals led by Connecticut’s Rosa DeLauro and Illinois’s Jan Schakowsky are introducing a bill that would allow traditional employer-based insurance to continue while enrolling the uninsured automatically in expanded versions of Medicare and Medicaid.

Jayapal’s bill, H.R. 1384, is far more generous than that plan or the legislation proposed by Sanders.

It would expand Medicare to everyone over just two years and once in place would waive all co-pays, deductibles and premiums for the insured. Unlike Medicare now, it would cover long-term nursing home care. Private insurers would be banned from competing with the new Medicare for essential services but could offer new plans for elective procedures like plastic surgery, Jayapal said.

Jayapal and other supporters are focused on attracting more rank-and-file Democrats to the idea and addressing the qualms of their own leaders about embracing a concept that could cost tens of trillions of dollars while threatening the revenue of health providers and hospitals.

“It’s easy for people to shoot arrows at something at top-line level but when you really look at the problems of the existing health-care system, you really realize how desperate the situation is and what a pocketbook issue health care is for so many Americans,” Jayapal said. “We do want this discussion on Medicare for All to help drive the presidential race.”

Given Republican control of the Senate and President Donald Trump in the White House, Medicare for All advocates outside Congress are similarly realistic.

“We certainly see that is not going to be moving in the Senate,” said Melinda St. Louis of the Public Citizen advocacy group. “Our work over the next two years is to build the legislative record, to do the grassroots organizing and to do a big push after 2020.”

St. Louis and other advocates say they won’t be satisfied with just two hearings in this Congress on the Medicare idea and will be working to secure more sponsors and hearings in the powerful Ways and Means and Energy and Commerce committees.

“Having a hearing is progress but that’s not the end goal. We want it ultimately to be enacted into law,” said Jean Ross, co-president of National Nurses United, a group that’s long supported Medicare for All.

Adam Green of the Progressive Change Campaign Committee organization has threatened to support a primary challenge against Ways and Means Chairman Richard Neal of Massachusetts if he refuses to hold hearings on the plan. The group also complained that Neal was moving too slowly to demand Trump’s tax returns.

Neal said Monday that his panel may at some point hold a hearing addressing “expanded access” to heath care that includes discussion of Medicare for All.

Energy and Commerce Chairman Frank Pallone of New Jersey said his committee, which also has jurisdiction over Medicare, needs to stay focused on protecting Obamacare.

The GOP has been eager to use Medicare for All as a political weapon. “Democrats are fully embracing socialism and a complete government takeover of the American health care system. Democrats’ radical plan will rip health care from 158 million Americans. Taxes would skyrocket and access to care would slow to a crawl,” House Republicans said in a statement Monday.

Industry Opposition

Industry advocates are also escalating their attacks.

“The result would be a single, one-size-fits-all system for every American — young or old, sick or healthy — that leads to longer wait times and a lower quality of care for everyone, while health care decisions are shifted away from doctors and patients to politicians and bureaucrats in Washington,” said Lauren Crawford Shaver of the Partnership for America’s Health Care Future, an health provider and insurance industry coalition.

Most of the Democrats who last November unseated Republicans to give their party control of the House haven’t put their support behind Medicare for All, partly because it’s seen as an aspiration rather than a practical solution to issues like rising health insurance premiums.

The divided Democrats skirmished last week about who would appear at Tuesday’s hearing.

After grumbling from liberal activists that witnesses were not enough in favor of Medicare for All, the leadership announced the addition of Ady Barkan, of the Center for Popular Democracy, who has amyotrophic lateral sclerosis.

Republicans are presenting their own witnesses, including Charles Blahous, of the Mercatus Center, who has estimated that the Sanders version of Medicare for All would require $32 trillion in increased federal spending over a decade.