Now that Republicans control both houses of Congress and the presidency, their threat to repeal the Affordable Care Act no longer is a pipe dream, but the trick now is to transition to a new system that doesn’t rip coverage away from the 20 million Americans who have signed up in recent years.

President Barack Obama’s signature legislative achievement was signed into law March 23, 2010, but didn’t come into full force until last year. Republicans hate the mandate that requires all adults to obtain coverage or face fines, they hate that the federal government has become the primary regulator of healthcare, and they hate that the law specifies what insurance companies need to cover.

Republicans said Wednesday they intend to repeal the ACA by early next year but possibly delay the effective date three years to figure out with what they want to replace it. Part of the balancing act will entail convincing insurers not to bail on the healthcare marketplaces.

“I think once it’s repealed, you will have hopefully fewer people playing politics and [instead] coming together to try to find the best policy,” House Majority Leader Kevin McCarthy, R-Calif., told Politico, adding once there’s “a date certain that something’s going away … you know you have to have something done.”

House Republicans have voted 60 times to repeal the ACA since it was enacted. During the campaign, President-elect Donald Trump repeatedly said the law would be repealed and replaced with something “much better.”

After the election, however, Trump said some elements of the ACA should be preserved, like the guarantees of coverage for people with pre-existing conditions and allowing children to stay on their parents’ plans until they reach 26 years of age.

Further complicating the Republicans’ path forward is a study released by Kaiser Family Foundation that indicates only about a quarter of Americans want the law repealed entirely.

“The flaws in Obamacare are obvious to me. The solutions are much harder,” Sen. Lindsey Graham, R-S.C., told Politico.

Health Secretary-designate Rep. Tom Price, R-Ga., is a longtime critic of the ACA — and a doctor. Among the changes he has proposed, the Fiscal Times reported, are eliminating the state-run marketplaces, individual mandates and federal tax credits for low-income participants. Instead, he would like to see tax credits pegged to a person’s age, ranging from $1,200 to $3,000 to partially cover premiums and out-of-pocket costs.

For a pre-existing condition or chronic illness to be covered, consumers would have to prove they had continuous coverage for the preceding 18 months to prevent people from obtaining coverage only after they become ill.

Senate Health Education, Labor and Pension Committee Chairman Lamar Alexander, R-Tenn., said he’d like to have a replacement plan in hand before the ACA is repealed, an approach favored by Price.

But House Speaker Paul Ryan said Wednesday he’s in favor of taking care of repealing the law immediately.

One approach under consideration is to take the law on in pieces rather than by passing one massive bill, an approach that likely would drag out the process and possibly produce a backlash from voters who want to see action after six years of bluster.

Ryan has offered a proposal he says would give patients and doctors more control and foster competition among insurers.

Like the ACA it would set up state insurance exchanges and protect those with pre-existing conditions. It also would auto-enroll people at points of service and give states the power to form multistate high-risk pools.

The proposal would provide tax credits for obtaining coverage and improve Health Savings Accounts by allowing premiums to be paid from them and increasing the amount of before-tax money that can be contributed to them.

The plan also calls for improvements to Medicaid and privatizing Medicare.