The Republicans are facing a 16 million person problem.

With the Obama administration announcing this month that some 16 million people have obtained health insurance since the passage of the Affordable Care Act, the Republicans’ intense focus on completely repealing the law is increasingly looking unrealistic.

Surveys suggest that the people who have received health insurance through the law generally like it. It’s exceeding rare that a state or the federal government grants people benefits and then takes them away. And even if the Supreme Court this summer strikes down subsidies under the ACA in states that have not set up their own health exchanges, millions of Americans will still pay little or nothing for health insurance because of the law.

Republicans blasted Obama for disrupting the health insurance of Americans to enact his policy vision, as the early days after the law's enactment including thousands of Americans having their existing insurance plans canceled. Now, with Obamacare more entrenched, Republicans would face the political backlash from a huge overhaul if they went through with their plans to repeal and replace the ACA.

“If you repeal Obamacare, but you don’t have a solution for that population, to me that’s not viable,” said Avik Roy, a conservative health care expert at the Manhattan Institute. “There’s a significant number of voters who are not going to take kindly to potentially messing with their health care and that is an important political problem.”

“If Republicans are going to campaign on taking health care away from millions of people, that’s going to be a tough sell,” Roy added.

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Roy is among a group of GOP policy wonks who want both Republicans in Congress and the 2016 candidates to develop detailed policy plans on health care. These experts argue Republicans must have an idea to make sure people can still afford their health insurance if the Supreme Court rules that residents in the 34 states that rely on the federal health care exchange can’t use subsidies.

And even if the Court sides with the Obama administration in the King v. Burwell case and leaves Obamacare largely in place, these experts say it is important to develop a coherent replacement plan that a Republican president could implement if he or she were elected in 2016.

“If they really want to displace large chucks of the law, they are going to have to fill it in with in their own vision. Going back to the pre-2010 status quo is not an option,” said James Capretta, former George W. Bush administration official who is now a senior fellow at the Ethics and Public Policy Center.

There are already outlines of such ideas emerging among Republicans. Nebraska Sen. Ben Sasse has proposed, in the event the Supreme Court strikes down the subsidies in states without health care exchanges, that Republicans offer a bill that would extend those subsidies for another 18 months, so Americans would not lose their health insurance. This would in effect leave the future of the ACA to the next president.

A group of influential GOP health care experts has written a proposal that would rewrite Obamacare, but would attempt to keep in place some of its key provisions, such as making it easier for Americans with pre-existing health conditions to buy insurance. It would seek to use tax credits to expand insurance to low-income people, instead of the reliance on Medicaid in the ACA.

So far though, the views of the Republicans’ conservative wing, not its policy wonks, are dominating how the party handles health care policy. And conservative activists still want the law completely gutted.

The House of Representatives this week passed a budget that calls for the repeal of the ACA, with few details on how to offer health insurance to those who would be affected. In his announcement of a presidential run this week, Sen. Ted Cruz of Texas emphasized his promise of “repealing every word of Obamacare,” while saying little about how he would offer health insurance to people instead.

In an op-ed this week, Sen. Marco Rubio of Florida, another Republican presidential candidate, said he was preparing for the “post-Obamacare era.”

There is little sign such a time is coming. And on the Democratic side, there is increased confidence about the law.

In 2010, 2012 and 2014, most Democratic candidates, aside from Obama, were reluctantly to publicly trumpet the ACA, which polls show remains deeply controversial.

Hillary Clinton though appears to view the law as an asset in the early stages of her expected presidential run.

“#ACA@5: 16m covered. Young ppl. Preexisting conditions. Women get better coverage. Repeal those things? Embrace them!,” Clinton said in a Twitter message on Monday, the fifth anniversary of when Obama signed the law.

Her message included a picture of Clinton hugging Obama in 2010 in the days after the ACA was enacted.

“16 million Americans have gotten coverage, millions of young people are able to stay on their parents’ plans, insurance companies can no longer discriminate against people with preexisting conditions or charge women higher rates just because of our gender," Clinton said in a speech on Tuesday.

“That is an important record and one that there is a lot of be proud of,” she added.