Confronted with a real falsehood, however, PolitiFact gets soft. An Obama ad had claimed that Paul Ryan’s Medicare plan could raise costs for senior citizens by $6,400 — and PolitiFact rated it “mostly true,” and then backed down to “half true.” It is wholly false. Ryan’s most recent plan was designed so that seniors will never have to pay more for Medicare than they would under Obama’s budgets. PolitiFact claims that Obama is giving an accurate characterization of an older version of Ryan’s plan. It justifies Obama’s attack on this outdated plan because the Congressional Budget Office has not evaluated the new one. Yet no evaluation by the CBO is needed to reject Obama’s attack. Ryan’s plan guarantees that seniors would always have at least one insurance option that will cost them no more than Medicare does, and at least one option that will leave them ahead.

PolitiFact sometimes rates Democratic claims as false and Republican ones as true, and Republicans on those occasions are often tempted to cite the organization in their defense. They should resist the temptation, or at least preface any comment with an acknowledgment of PolitiFact’s limited credibility. (As in, “Even PolitiFact saw through the latest Obama ad.”)

PolitiFact has just introduced a new “Settle It!” app which it calls, with amazing gall, an “argument ender.” Maybe it’s liberal bias that explains PolitiFact’s blown calls. Whatever the reason, it is no good at distinguishing between truth and falsehood, which is to say at its professed mission. It should therefore give itself a “pants on fire” rating and shut itself down.