WASHINGTON — The Republican Party’s failure to pass a health care bill has left most Democrats overjoyed, confident now that former President Barack Obama’s landmark Affordable Care Act will remain law for the foreseeable future. But not everybody in the party is satisfied.

A small but growing group of liberals — some of them leaders in the Democratic Party — are already pushing their colleagues to embrace a more progressive vision for health care.

At the top of this band of activists’ wish list is a radical change, converting the country into a so-called single-payer system that would act much as Medicare does for people 65 and older. But they’re also pursuing a series of smaller objectives, including letting people who sign up for the ACA’s state-based exchanges enroll in a government-backed plan, known as the public option.

It’s a debate that’s likely to shape the Democratic Party for years to come, as its leaders grapple with the issue’s deep political risks — a lesson many of them learned well after Obamacare passed in 2010 and immediately became a focal point of GOP attacks.

As former presidential candidate and liberal icon Bernie Sanders put it, the ACA is “far, far, far from perfect.”

“We have got to have the guts to take on the insurance companies, the drug companies, and move forward toward am Medicare for all, single-payer program,” the senator from Vermont said on MSNBC after the GOP’s health care bill died in the House. “And I’ll be introducing legislation shortly to do that.”

A Sanders spokesman confirmed the senator will introduce single-payer legislation in the coming weeks, similar to measures he’s previously pushed.

Even before the implementation of Obamacare, most Democrats dismissed serious talk of creating a single-payer system. Many in the party feared the politics of an enormous expansion of government and the disruption it would bring to the health care market.

Progressive activists now wonder if the political calculus has shifted in their favor. To them, the failure of the GOP plan supported by President Donald Trump — the American Health Care Act — was proof that the public will reject any plan that reduces coverage.

That leaves one option for reform, these Democrats say: legislation that increases government involvement and coverage for the poor and uninsured.

“We’ve check-mated Republicans,” said Kaitlin Sweeney, spokeswoman for the Progressive Change Campaign Committee. “The only choice is to go for a forward looking solution that lowers costs improves care and covers everyone. And that’s Medicare for all.”

Absent a plan for change, she added, Democrats will be forced to defend an unpopular existing system that will anger moderates and underwhelm the party’s base.

“Sticking with a defensive posture and just protect the status quo is not going to be something that fires up voters in 2018 or 2020,” Sweeney said. “It’s not something you can hold to as an effective strategy to go after Republican.”