Supporters of President Obama are working overtime to backtrack from his promise that "If you like your health-care insurance, you can keep it. Period." While the president has conceded that this statement was inaccurate, the administration doesn't seem to have learned its lesson. The damage control plan is to spread another falsehood about the Affordable Care Act.

The claim this time is that the health-care "cost curve is bending, and the ACA is a significant part of the reason." That was what David Cutler—an...