WASHINGTON In promoting the health care law, President Barack Obama is repeating his persistent and unsubstantiated assurance that Americans who like their health insurance can simply keep it. Republican rival Mitt Romney says quite the opposite, but his doomsday scenario is a stretch.

After the Supreme Court upheld the law last week, Obama stepped forward to tell Americans what good will come from it. Romney was quick to lay out the harm. But some of the evidence they gave to the court of public opinion was suspect.

A look at their claims and how they compare with the facts:

OBAMA: If youre one of the more than 250 million Americans who already have health insurance, you will keep your health insurance. This law will only make it more secure and more affordable.

ROMNEY: Obamacare also means that for up to 20 million Americans, they will lose the insurance they currently have, the insurance that they like and they want to keep.

THE FACTS: Nothing in the law ensures that people happy with their policies now can keep them. Employers will continue to have the right to modify coverage or even drop it, and some are expected to do so as more insurance alternatives become available to the population under the law. Nor is there any guarantee that coverage will become cheaper, despite the subsidies many people will get.

Americans may well end up feeling more secure about their ability to obtain and keep coverage once insurance companies can no longer deny, terminate or charge more for coverage for those in poor health. But particular health insurance plans will have no guarantee of ironclad security. Much can change, including the cost.

The non-partisan Congressional Budget Office has estimated that the number of workers getting employer-based coverage could drop by several million, as some workers choose new plans in the marketplace or as employers drop coverage altogether. Companies with more than 50 workers would have to pay a fine for terminating insurance, but in some cases that would be cost-effective for them.

Obamas soothing words for those who are content with their current coverage have been heard before, rendered with different degrees of accuracy. Hes said nothing in the law requires people to change their plans, true enough. But the law does not guarantee the status quo for anyone, either.

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Health care debate claims vs. facts