The news that Mitt Romney is going to make a major speech on health care at the University of Michigan on Thursday suggests that the former Massachusetts governor is coming to grips at last with his presidential candidacy’s greatest problem. But if, as Mark Helprin claims in Time magazine, the GOP contender intends to repeat his argument that the government health-care bill he passed in Massachusetts is really, really different from Obamacare, he’s wasting his time. Even worse, if Romney thinks he can square this circle by presenting a detailed plan for a new health-care program that will replace Obama’s legislation, he is utterly deluded.

The reasoning behind Romney’s decision to address this issue now is sound. Romney’s history on health care is dooming his presidential bid. No Republican who has already pushed through a government program like his is going to be nominated, let alone elected president. So Romney must somehow put it behind him if he is to move on and use his money, personality and mainstream credibility on other issues to ride to the nomination.

But it’s far from clear that this is possible. And so long as Romney stands by his record in Massachusetts, it is absolutely impossible.

As for Romney’s new plan, it might be amazing, brilliant, incredible, astonishing—but no one will be listening. The only thing that counts in this conversation is whether Romney is going to stick with the lame excuses he has been mouthing so far to talk his way out of the rhetorical dead end he finds himself in. If he says now that he was wrong when he was governor to push for such a plan, it will be seen as another Romney flip-flop like his on-again, off-again opposition to abortion. If, as planned, he tries to assert that he was right then and right again now, no one will believe him.

Mitt Romney may make sense on Thursday and might even be eloquent in defense of his past stands and his future plans for health care in this country. But given the impossible hand he has been dealt on the issue, it isn’t likely that anything he says will do his candidacy much good.