JAMES TARANTO: ‘Shut Up’ Is No Argument: The illiberal left lacks confidence in its ideas.

“The debate over repealing this law is over,” President Obama declared last Tuesday in reference to ObamaCare. April Fool! By the end of the week some of Obama’s most loyal media supporters were proving him wrong–by repeating his arguments.

“Is there any accountability in American politics for being completely wrong?” demanded the Washington Post’s E.J. Dionne in his Thursday column. “Is there any cost to those who say things that turn out not to be true and then, when their fabrications or false predictions are exposed, calmly move on to concocting new claims as if they had never made the old ones?”

It won’t surprise you to learn that Dionne did not demand accountability from Obama and the other politicians who sold ObamaCare on the fraudulent promise “if you like your plan, you can keep your plan.” Rather, he asserted that the administration’s claim of having “hit its original goal . . . of signing up more than 7 million people through its insurance exchanges” was a definitive refutation of any notion that ObamaCare is “doomed.”

What about insurance cancellations, narrow networks, high deductibles, blown deadlines, work disincentives, adverse selection and the law’s continuing political unpopularity? Dionne dispenses with all these problems in one sentence: “To be sure, the law could still face other problems, blah, blah, blah.”

The next day it was former Enron adviser Paul Krugman’s turn.

He’s well practiced at telling people to shut up.

Related: Joel Kotkin: The spread of ‘debate is over’ syndrome: On climate and other issues, many in academia, media, government insist their viewpoint is unassailable and won’t tolerate dissent. They’re insecure about their ability to persuade, but more confident of their ability to coerce.