For all the challenges still facing Obamacare and its supporters, conservative health wonks are increasingly cautioning Republicans that the politics of the issue have changed in the wake of the 7 million initial sign-ups.

Simply repealing the law is no longer an option, they warn, even if Republicans gain the power to do so. If they want to unwind the law, the least they’ll have to do is coalesce around health care solutions of their own, lest they strip away benefits for millions of Americans without a plan of their own. And the party is far from a consensus on how they’d replace the law.

This new dynamic is slowly setting in among GOP lawmakers and top-level candidates. In a Washington Examiner op-ed Monday, Sen. Mike Lee (R-UT) and Nebraska Senate candidate Ben Sasse warned that “Republicans can’t beat Obamacare without effective health care solutions of their own.”

“If we are unwilling or unclear, the president will continue to mislead, government will continue to grow, and our healthcare system will continue to unravel,” Lee and Sasse wrote. “The American people deserve more than Obama’s false choice between big-government solutions and cold indifference. By articulating a conservative vision for the American people, Republicans can build trust and offer honest solutions.”

“Our mission has only begun,” the Republicans concluded.

There is internal dissent on whether Republicans ought to come up with an alternative. One congressional GOP health aide, who was granted anonymity to speak candidly, said his party is as determined as ever to fight Obamacare, and will remain so as long as it exhibits failure. He said devising an alternative is fraught with the difficulty of crafting a new benefits structure that doesn’t look like the Affordable Care Act.

“If you want to say the further and further this gets down the road, the harder and harder it gets to repeal, that’s absolutely true,” the aide said. “As far as repeal and replace goes, the problem with replace is that if you really want people to have these new benefits, it looks a hell of a lot like the Affordable Care Act. … To make something like that work, you have to move in the direction of the ACA. You have to have a participating mechanism, you have to have a mechanism to fund it, you have to have a mechanism to fix parts of the market.”

It sheds light on why Republicans haven’t yet followed through on the “replace” component of their “repeal and replace” mantra, more than four years after Obamacare was enacted. The popular parts of the law, most notably the preexisting conditions guarantee, are unsustainable without unpopular parts like the individual mandate. Unraveling the parts people dislike means unraveling the whole structure, and rebuilding the well-liked elements is difficult without arriving at a similar place as Obamacare.

Republican leaders haven’t flinched on wiping out the law, but they’re careful to emphasize that they don’t simply want to return to the pre-Obamacare status quo. Calling for repeal last week, Speaker John Boehner (R-OH) said, “We will also continue our work to replace this fundamentally-flawed law with patient-centered solutions focused on lowering health care costs and protecting jobs.”

“We are about proposing real health care reform that will be patient centered — and a plan that we will put forward this year,” House Majority Leader Eric Cantor (R-VA) told reporters on Tuesday. Cantor, who is leading GOP efforts to craft an alternative to Obamacare, said House committee chairs and Republican leaders are working together “we can coalesce around a real health care reform plan.”

It remains to be seen if there’s light at the end of that tunnel.

The upside for Republicans is that a message of repeal will probably suffice through the 2014 congressional elections, where the electorate is older, whiter and more conservative, giving Republicans a significant advantage. The law remains unpopular, and it’ll be a slog for Democrats to change that by November.

“My guys have not thrown up the white flag and said let’s give up. I think they still have fights they want to have [on Obamacare],” said the GOP health aide. “That said, could it ever truly be repealed? I don’t think it was ever possible to be repealed unless there was a massive electoral shift.”