USA Today reports: “The health care overhaul that President Obama intended to be the signature achievement of his first term instead has become a significant problem in his bid for a second one, uniting Republicans in opposition and eroding his standing among independents.” After years of promising that we would learn to like Obamacare, the president is now confronted with a harsh electoral reality:

In a USA TODAY/Gallup Poll of the nation’s dozen top battleground states, a clear majority of registered voters call the bill’s passage “a bad thing” and support its repeal if a Republican wins the White House in November. Two years after he signed the Patient Protection and Affordable Care Act — and as the Supreme Court prepares to hear arguments about its constitutionality next month — the president has failed to convince most Americans that it was the right thing to do.

Fifty-three percent of registered voters in the identified swing states think Obamacare is a “bad thing,” while only 38 percent say it is a good thing. Nationwide, 50 percent say it is a bad thing and 42 percent say it is a good thing.

Meanwhile, 75 percent in swing states and 76 percent nationally think the individual mandate is unconstitutional. Maybe Justice Anthony Kennedy (widely seen as the decisive vote) will be less nervous about striking down a statute with the understanding that he won’t incur the wrath of popular opinion, but the real import of that finding is that there could well be a hue and cry if the Supreme Court doesn’t strike it down.

Romney’s position, as we have known for some time, is harmed by Romneycare. But perhaps it is not as negative a factor as his opponents wish: “Among Republicans and Republican-leaning independents in the battleground states, 27% say they are less likely to support him because he signed a Massachusetts law that required residents to have coverage. Just 7% say it makes them more likely to back him.”

All of this suggests Romney should put some meat on the bones of his own health-care plan. His pledge to repeal Obamacare isn’t sufficient for those anti-Romney conservatives who refuse to believe anything he says, but for the persuadable Republicans as well independent voters, he would be wise to repeat why Obamacare has to go (it raises taxes, doesn’t end the cost curve, will expand the debt, etc.) and tell us, with more specificity, what his own plan would look like.

Romney has already told us what he’d do with Medicare (enact a premium support plan with traditional Medicare as one option) and Medicaid (block-grant it). But his plans for the rest of the health-care system) remain vague. He, at times, has embraced many of the ideas Sen. John McCain (R-Ariz.) put forth in his 2008 presidential run (e.g., equalizing tax treatment of individually purchased and employer-provided plans, tort reform, allowing interstate insurance sales). But just as he needed to put forth a more detailed tax reform plan and did (which pleased some fiscal conservatives), he should do the same with a health-care plan.

If he does and he’s the nominee, it will then not be simply “Obamacare vs. the guy who is promising to repeal Obamacare,” but “Obamacare vs. a conservative health-care reform plan.”

Certainly, Romney is still scrambling to win the nomination and to explain his other positions, but the sooner he rolls out a credible conservative alternative to Obamacare, the sooner, I would guess, he’ll be able to make some progress with persuadable conservatives and capi­tal­ize on the national aversion to Obamacare.