Mark Halperin reports that Mitt Romney is set to give a major speech laying out his plan to repeal and replace health reform, in order to get ahead of an issue that has bedeviled him with conservatives: Romneycare, his number one achievement, was the model for the hated Obamacare.

Halperin argues that this is “smart,” because it will give him a chance to “explain his record on this issue.” But Halperin also notes: “Romney won’t back off his past statements on his Massachusetts health care law.”

Please. Can we cut through the B.S. here? If Romney really isn’t going to back off Romneycare — and won’t fully repudiate the individual mandate at its core — then it won’t matter what he proposes. His speech won’t solve his political problem at all, at least with conservative opinion-makers.

They are angry with Romney because he employed a policy tool that they have come to regard as tyranny, now that it was used as the lynchpin for Obamacare. Romney has countered that his plan employed the mandate on the state level, while Obama’s is federal.

And it’s true, as Romney says, that he has long advocated a federalist approach to health reform. On Thursday, according to his office, he will call for an approach that will “restore to the states the responsibility and resources to care for their poor, uninsured, and chronically ill.”

But whatever the merits of his proposal, it’s unclear why it would solve his main political problem. When it comes to the individual mandate, many conservatives don’t care about the state-versus-federal distinction he makes. They hate the mandate whether it’s employed on the state or federal level.

It isn’t fair to Romney that he’s boxed in this way. As left-leaning groups like point out (mischievously), Romney’s plan was in many ways a policy success. Romney himself has said he’s proud of it. So he can’t repudiate it without feeding another major vulnerability — the perception that he’s ideologically malleable and will say anything to get elected.

But until Romney fully renounces the policy idea at the core of his (and Obama’s) achievement — until he severs his Gordian Knot — conservative opinionmakers won’t forgive him. Short of that, whatever he says on Thursday won’t change this basic dynamic, and could even reinforce the sense that he’s dancing around on the issue. Romney’s best hope is that 2012 GOP primary voters won’t see things the way conservative opinion leaders do.