When Vermont Sen. Bernie Sanders visited Beverly Hills last May, he made a full-throated appeal for California to “lead the country” and pass a pending state proposal to establish single-payer healthcare.

On Friday, he’ll return here for a San Francisco speech trumpeting his own higher-stakes plan — a bill to drastically overhaul the nation’s health-care system by covering everyone through Medicare .

The push for single-payer, in which the government pays for residents’ medical care, has already rattled California’s political landscape. Now, the Sanders measure brings an additional jolt, elevating the issue to a national debate that has implications for the future direction of the Democratic Party and early jockeying in the 2020 presidential race .

The Sanders plan has left proponents of state Senate Bill 562, the California proposal, elated, viewing the buzz in Washington, D.C., as an unequivocal boon to their efforts in Sacramento, which faltered this summer when the measure was shelved in the state Assembly.

“It phenomenally buttresses SB 562,” said RoseAnn DeMoro, executive director of the California Nurses Assn./National Nurses United, the bill’s most fervent supporter. “The fact is, it’s in the national narrative now.”

But the parallel state and federal proposals could also make an already thorny issue more difficult by laying bare the challenges facing California should it embark on the single-payer route alone — and ramping up the pressure for the state to establish itself as a national model.

Sanders, who has a huge liberal following in California from his presidential bid, has been an enthusiastic proponent of the state’s proposal, casting it as a head start for his national single-payer ambition.

“Please make my life easier,” he pleaded in May, endorsing the bill by state Sen. Ricardo Lara (D-Bell Gardens) that was then winding its way through committee hearings. It was abruptly halted by Assembly Speaker Anthony Rendon (D-Paramount) several months later, but is still eligible for consideration next year. At the time, Rendon called the plan “woefully incomplete.”

For now, the two bills face vastly different political terrains. Sanders’ measure, which was rolled out last week, would have to clear a Republican Congress and survive President Trump ’s veto pen, an almost unimaginable scenario. In California, the prospect is theoretically less futile with Democrats dominating the state Capitol, although this year’s stumble showed how resistance to single-payer is not simply partisan.

Policy-wise, Sanders’ bill echoes California’s. Both proposals would do away with nearly all out-of-pocket health-care costs for residents, including premiums and co-pays. Both would dramatically reduce the role of private insurance companies, with government filling that role instead.

While proponents of each bill have floated potential financing schemes, neither piece of legislation includes tax hikes or a specific way to cover costs.

Both measures have been framed by supporters as a rejoinder to the repeated attempts by Republicans in Congress to repeal the Affordable Care Act , including a new Obamacare overhaul poised for a Senate vote next week.

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Lara, the author of SB 562, backs the Sanders plan. But despite the bills’ similarities, other California politicians have reacted differently to the two proposals.

U.S. Sen. Kamala Harris is one of 16 Democratic senators to co-sponsor Sanders’ bill.

“United States taxpayers deserve a better return on their investment, and that's why I'm supporting Medicare for All,” Harris said in a statement. “It is about saying that healthcare is a right for all, not a privilege for a few.”

Harris did not take a position on the California bill, and her office did not address a reporter’s specific questions on the state-level effort this week.

Lt. Gov. Gavin Newsom , a 2018 gubernatorial hopeful who, along with Sanders, will address the nurses’ union Friday, has been unequivocal in his support for the Sanders bill.

But he has been more circumspect on his thoughts on SB 562, explaining in an interview that he wanted to see the legislative process in Sacramento “run its course.”

“The bill's not perfect. It's not complete,” Newsom said. “The end result would hardly look like it looks today had it had a chance to process through the Legislature.”

One of Newsom’s Democratic rivals in the governor’s race, former Los Angeles Mayor Antonio Villaraigosa , said he supports the concept of having national single-payer health-care coverage, but he opposed SB 562.

“I don’t support it because it doesn’t have a funding plan,” Villaraigosa said. “The notion that we would just transfer to a single-payer system on our own with the price tag of $400 billion is not something people see as feasible.”

Single-payer backers such as DeMoro expressed little patience with distinguishing support for a state proposal versus a national one.

“If you're a single-payer advocate, you're going to support SB 562. If you're just politically posturing, you might not,” DeMoro said. She added she has “confidence” that Newsom, whom her group endorsed nearly two years ago, sufficiently backs the state bill.

A state-level single-payer system in California is attainable, according to health-care experts.

“We are large enough to do what needs to be done,” said Gerald Kominski, director of UCLA’s Center for Health Policy Research. “We've got a large enough pool of people. We've got a strong economy. So we could go it alone.”

As long as there’s a Republican Congress and a Republican president, everyone knows this is an organizing tool rather than an immediate threat to pass. — Eddie Kurtz, president of Courage Campaign, on Sen. Bernie Sanders' Medicare for All bill

Still, there are unique snags to a state-only system. Most significantly, California would need to get permission from the federal government to repurpose dollars from Medicare, Medicaid and other programs. That prospect appears hazy under Trump, who called single-payer a “curse on the U.S.” in a recent tweet. And California’s state constitution has spending limits and rules on how revenue must be spent that serve as obstacles to using new taxes for increased healthcare spending.

A California single-payer system could also be more vulnerable to “medical tourists” from other states establishing residency here — a relatively easy step under the proposal — to take advantage of free care.

Sanders’ proposal essentially expands Medicare, a single-payer system already in place. California, however, has no equivalent program; it would have to build one from scratch.

Medicare “is a framework that, I think, most people can get their arms around. It’s a process that provides for at least some understanding and familiarity,” Newsom said. “At the state level, the requirements are very different …. It’s a more challenging frame.”

Single-payer advocates in the state said while they’re thrilled by Sanders’ proposal, their primary efforts will still be in California where such a plan is more politically possible.

The progressive group Courage Campaign convened liberal activists this week in Sacramento to strategize on how to push ahead with a state-level health-care overhaul.

“As long as there’s a Republican Congress and a Republican president, everyone knows this is an organizing tool rather than an immediate threat to pass,” said Eddie Kurtz, the group’s president. “It’s wonderful to have that goalpost out there.”

Assemblyman Kevin McCarty (D-Sacramento), a co-author of SB 562 who nonetheless called the bill not “ready for prime time,” said he didn’t expect lawmakers to cede the issue to Congress.

“The best way to do it and the most viable is to have a national plan for this,” McCarty said. “Does that mean California should sit around and wait for the nation to do it? No. I think we'll be evaluating how to do it.”

The national debate underscores how high the stakes will be. Proponents are hoping California will serve as Massachusetts did for the Affordable Care Act, establishing a model the country can follow.

The potential of being an archetype also comes with more responsibility to craft the best policy, said Rendon, who has urged broadening the healthcare overhaul debate beyond SB 562. He is facing a recall effort for deciding to shelve that bill.

“The possibilities of a national system changes the conversation,” Rendon said. “If we're going to do universal healthcare in California — whatever manifestation that may take — there may be more of a need to get it right than there would have been otherwise.”

Times staff writer Phil Willon in Sacramento contributed to this report.

melanie.mason@latimes.com

Follow @melmason on Twitter for the latest on California politics.

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Updates from Sacramento

UPDATES:

9:20 p.m.: This article was updated with more information about how single-payer faces potential constitutional challenges.

This article was originally published at 12 a.m.