At his press conference today, President Obama scrambled to “clarify” his promise to Americans on health care. It won’t work.

For months now, going all the way back to the early days of the 2008 campaign, President Obama has been promising Americans that, if they like the insurance plan they have, they will get to keep it. He didn’t just mention this once or twice. It was a staple of his pitch, repeated over and over again.

Of course, he made the promise for sound political reasons. His strategists are listening carefully to what their focus groups have to say, and they are hearing the same message Americans have been delivering on health care for years. Yes, many voters wouldn’t mind seeing health-care reform pass in Congress because they perceive problems of cost and coverage that they would like to see fixed. But they don’t want to trade in their good job-based insurance for an untested, government-heavy program.

The problem for President Obama is that he and his allies want to pass an untested, government-heavy program — but without saying so.

Every bill now being drafted in Congress would establish a “pay or play”-type choice for employers: Employers must either offer government-approved coverage to workers (“play”) or pay a tax to the government instead to partially cover the costs of their premiums for insurance secured through a new “exchange” system. For years, Democrats have argued that this construct would ensure that reform “builds upon” the employer-based insurance system. But, in fact, the Democratic approach to reform would have exactly the opposite effect. Employers would get burdened with new costs and insurance requirements, even as the government used price controls to offer a government-run insurance option with artificially low premiums and provided new subsidies for coverage only for workers getting insurance through the “exchange.” That’s a recipe for dismantling job-based insurance. The Lewin Group has estimated that, assuming certain plausible specifications, some 119 million people would end up leaving job-based coverage for a government-run plan as employers opted to “pay” rather than “play.”

Faced with incontrovertible evidence that he and his allies have no intention or ability to fulfill their commitment to Americans regarding their current coverage, President Obama decided today at his press conference to try to redefine the promise. What he meant, he now says, is that the government wouldn’t force people out of their health-care plan. If tens of millions of people get pushed out of their current coverage, it would be because firms chose to drop their insurance plans — never mind the fact that they would do so based on the financial incentives the government put in place.

The president’s “clarification” seems highly unlikely to be the final word on this. For starters, it doesn’t matter much to the voting public who pulls the trigger. They don’t want today’s stable, job-based coverage turned upside by “reform.” When they hear that tens of millions of people will get moved out of employer plans and into the “government option,” they will wonder if they themselves will have to switch insurance — and most don’t want to. The president’s comments today aren’t likely to put their fears to rest.

Then there’s the issue of the president’s credibility. The straightforward commitment that “you can keep what you have” was stated over and over again. In fact, it helped the president get elected in the first place. If his clarification today was what he meant all along, why didn’t he just so say sooner? That question seems likely to cross a few people’s minds.