There’s a lot of fuzzy math in American politics, but Representative Pete Sessions of Texas, the chairman of the House Rules Committee, recently set a new standard when he declared the cost of Obamacare “unconscionable.” If you do “simple multiplication,” he insisted, you find that the coverage expansion is costing $5 million per recipient. But his calculation was a bit off — namely, by a factor of more than a thousand. The actual cost per newly insured American is about $4,000.

Now, everyone makes mistakes. But this wasn’t a forgivable error. Whatever your overall view of the Affordable Care Act, one indisputable fact is that it’s costing taxpayers much less than expected — about 20 percent less, according to the Congressional Budget Office. A senior member of Congress should know that, and he certainly has no business making speeches about an issue if he won’t bother to read budget office reports.

But that is, of course, how it’s been all along with Obamacare. Before the law went into effect, opponents predicted disaster on all levels. What has happened instead is that the law is working pretty well. So how have the prophets of disaster responded? By pretending that the bad things they said would happen have, in fact, happened.

Costs aren’t the only area where enemies of reform prefer to talk about imaginary disasters rather than real success stories. Remember, Obamacare was also supposed to be a huge job-killer. In 2011, the House even passed a bill called the Repealing the Job-Killing Health Care Law Act. Health reform, opponents declared, would cripple the economy and in particular cause businesses to force their employees into part-time work.