“No. 1,” declared Mitt Romney in Wednesday’s debate, “pre-existing conditions are covered under my plan.” No, they aren’t — as Mr. Romney’s own advisers have conceded in the past, and did again after the debate.

Was Mr. Romney lying? Well, either that or he was making what amounts to a sick joke. Either way, his attempt to deceive voters on this issue was the biggest of many misleading and/or dishonest claims he made over the course of that hour and a half. Yes, President Obama did a notably bad job of responding. But I’ll leave the theater criticism to others and talk instead about the issue that should be at the heart of this election.

So, about that sick joke: What Mr. Romney actually proposes is that Americans with pre-existing conditions who already have health coverage be allowed to keep that coverage even if they lose their job — as long as they keep paying the premiums. As it happens, this is already the law of the land. But it’s not what anyone in real life means by having a health plan that covers pre-existing conditions, because it applies only to those who manage to land a job with health insurance in the first place (and are able to maintain their payments despite losing that job). Did I mention that the number of jobs that come with health insurance has been steadily declining over the past decade?

What Mr. Romney did in the debate, in other words, was, at best, to play a word game with voters, pretending to offer something substantive for the uninsured while actually offering nothing. For all practical purposes, he simply lied about what his policy proposals would do.