Avik Roy documents for Forbes readers how “the self-appointed guardians of truth and justice” at PolitiFact changed their tune about President Obama’s now laughable claim that those who liked their pre-Obamacare health insurance plans could keep them.

[I]n its article detailing why the President’s promise was a lie, PolitiFact neglected to mention an essential detail. In 2008, at a critical point in the presidential campaign, PolitiFact rated the “keep your plan” promise as “True.” The whole episode, and PolitiFact’s misleading behavior throughout, tells us a lot about the troubled state of “fact-checking” journalism.

On October 9, 2008, Angie Drobnic Holan of PolitiFact published an article using the site’s “Truth-O-Meter” to evaluate this claim: “Under Barack Obama’s health care proposal, ‘if you’ve got a health care plan that you like, you can keep it.’” The article assures us in its headline that “Obama’s plan expands [the] existing system,” and continues that “Obama is accurately describing his health care plan here…It remains to be seen whether Obama’s plan will actually be able to achieve the cost savings it promises for the health care system. But people who want to keep their current insurance should be able to do that under Obama’s plan. His description of his plan is accurate, and we rate his statement True.” …

… As per PolitiFact’s usual M.O., Holan didn’t seek out any skeptical health-policy experts to suss out the veracity of Senator Obama’s signature claim. Instead, its sources included Jonathan Cohn, a passionate Obamacare supporter at The New Republic, and various interviews and statements of Mr. Obama. Holan simply took the “keep your plan” promise at face value, dismissing as dishonest anyone who dared suggest that Obama’s claim would be impossible to keep. “His opponents have attacked his plan as ‘government-run’ health care,” she wrote, the scare-quotes around “government-run” being visible to all.

PolitiFact’s pronouncements about Obamacare were widely repeated by pro-Obama reporters and pundits, and had a meaningful impact on the outcome of the election. Indeed, in 2009, PolitiFact won the Pulitzer Prize for its coverage of the 2008 campaign.

By the summer of 2009, with the White House safely in Democratic hands, Holan and PolitiFact evolved their evaluation of Obama’s promise. “On one level, Obama is correct,” Holan insisted in a new PolitiFact article, but now that “we finally have detailed bills to examine,” Holan found that Obamacare would “introduce new ways of regulating health insurance companies that will surely change the current health care system.” Surprise! …

… In the summer of 2012, after the Supreme Court upheld the constitutionality of Obamacare’s individual mandate, PolitiFact was back at it again, rating as “Half True” the President’s “keep your plan” promise. This time, the article was written and researched by another PolitiFact writer, Louis Jacobson, and edited by Angie Drobnic Holan, who had been promoted by PolitiFact from her previous reportorial role. …

… So that brings us back to the fall of 2013. As Obamacare’s battle station became operational, and tens of millions of health plans became illegal, PolitiFact was caught with its flaming pants down. Louis Jacobson rapped Valerie Jarrett for tweeting that “nothing in Obamacare forces people out of their health plans”—a claim Jacobson rated as “False,” even though PolitiFact had rated it as “True” and “Half True” before.

On November 4, Jacobson rated as “Pants on Fire” the President’s new claim that “what we said was, you can keep [your plan] if it hasn’t changed since the law passed.” Both pieces were edited by Angie Drobnic Holan, who had initially granted PolitiFact’s seal of approval to Senator Obama’s 2008 promise. Holan delivered the coup de grâce, declaring as PolitiFact’s “Lie of the Year” the “keep your plan” promise.

“The promise was impossible to keep,” says Holan in her December piece. Now she tells us! But none of the key facts that made that promise “impossible” in 2008 had changed by 2013.