By Susan Cornwell and Richard Cowan, Reuters–

President-elect Donald Trump and congressional Republicans have vowed to move quickly to repeal President Barack Obama’s signature healthcare law, but dismantling the program could leave tens of millions of Americans without healthcare.

Such an outcome could fuel a major backlash against Republicans, who control both houses of the U.S. Congress. The dilemma will be the focus of talks that Vice President-elect Mike Pence will have with Republican lawmakers on Wednesday on Capitol Hill.

At the same time, Obama is meeting with Democrats at the Capitol to figure out how to protect the Obamacare law from Republicans who want to repeal and replace it with a more market-oriented alternative.

Democratic leaders, Chuck Schumer of the Senate and Nancy Pelosi of the House of Representatives, are to hold a news conference after the session.

“The president’s priority and the president’s motivation is rooted in looking out for the interest of the 22 million Americans whose healthcare would be taken away if Republicans repeal the Affordable Care Act,” White House spokesman Josh Earnest told reporters.

Trump has vowed to protect some popular parts of the Obamacare law, such as barring insurance companies from denying coverage to people with pre-existing medical conditions. But he wants to replace it with a system that is “much better and much less expensive,” as he told Reuters on Oct. 25 after premium increases emerged in some healthcare markets.

Republican Representative Chris Collins, a liaison between the Trump transition team and Congress, said he did not expect Pence to have definite answers to detailed healthcare policy questions such as what timeframe should be considered for repealing the law.

The transition team, Collins said, is “not into that kind of meat and potatoes.”

A House Republican leadership aide said there are lots of Republican “ideas,” but it is too early to know what will end up in replacement legislation.

Representative Raul Labrador, a leading House conservative, asked on Tuesday where things stand with repeal and replace legislation, said there are six different proposals and all will have to circulate through various congressional committees.

“There’s just going to be hearings. The Democrats spent a lot of time screwing up the economy and screwing up healthcare, and it’s going to take us a lot of time trying to rectify it,” he said.

Asked about short-term bridges to help the insurance industry during a transition period, Labrador said, “The insurance industry got us into this mess. I think they’re going to have to pay the price for it.”

In a December letter to U.S. lawmakers, the American Academy of Actuaries highlighted the potential consequences of repealing or gutting the Affordable Care Act without a replacement.

“Delaying the effective date of repeal while a replacement is worked out likely won’t be enough to assure the stability and sustainability of the individual market,” the actuaries wrote in the letter. The individual market is where those not insured with a group, such as a workplace, go to buy insurance.

Repealing major parts of Obamacare, such as the requirement to participate in the individual insurance market, could create a cascade effect, causing “the risk pools to deteriorate and premiums to become less affordable,” the letter said.

The Heritage Foundation, a conservative think tank, said in a November policy paper that timing and sequencing the repeal of Obamacare was a complex issue and could take two budget cycles, 2017 and 2018.

(Additional reporting by Mike Stone; Writing by Steve Holland; Editing by Leslie Adler)