IRS Commissioner John Koskinen. Photo: Brendan Smialowski/AFP/Getty Images

Four and a half years ago, the IRS revealed that it had subjected numerous conservative political groups to excessive scrutiny, delays, and demands for paperwork. A scandal was born. President Obama apologized, newspaper headlines confirmed the agency’s guilt, and Congress scheduled investigatory hearings to confirm its suspicion that the Obama administration has sicced the agency on its enemies — just like Nixon, whose name was invoked with frequency.

Last night supplied the latest and probably final proof that the entire scandal was a fever dream. The Obama administration didn’t use the agency to target its opponents; indeed, as we now know conclusively, the IRS did not target conservatives at all. The sorry episode reveals a great deal about Washington but nothing whatsoever about a liberal bureaucratic plot.

The Treasury Inspector General for Tax Administration reviewed a decade of IRS handling of political organizations. It found that scores of liberal groups were subject to the same heavy scrutiny that conservative groups faced. This merely certified what had been perfectly clear all along. Within months of the “targeting scandal” breaking, evidence was already available to show that the IRS was giving political activists on the left the same treatment as those on the right. (The New York Times reported on this as early as June 2013.) Subsequent hearings turned up no evidence Obama had ordered the IRS to target conservatives because the IRS did not in fact target conservatives. The fact some conservatives had a hard time dealing with the IRS did not prove the IRS is targeting conservatives any more than some conservatives having a hard time renewing their driver’s licenses would prove the DMV is targeting conservatives.

And yet the scandal has lived on and on in the conservative mind. House Republicans have demanded the impeachment of the IRS commissioner; The House Republicans’ website continues to insist “The American people deserve answers”; last month, Republicans expressed outrage that the Department of Justice declined to prosecute former IRS official Lois Lerner, whose name has become a right-wing trigger-phrase akin to “Benghazi.”

Nobody has ever told the Republican base there is no IRS scandal. Pro-Trump and Never Trump Republicans are united in their fixed belief in this unicorn. Charlie Sykes’s new book, How the Right Lost Its Mind, which is primarily dedicated to the rise of the right-wing fever swamp and the role of the conservative media in allowing its fantasies to swell unchallenged, casually mentions — in the section explaining why conservatives have some legitimate grievances — “IRS targeting of Tea Party groups.” Fervently anti-Trump conservatives like Michael Gerson, George Will, Noah Rothman, and many others continue to cite the nonexistent scandal as if it were a real thing.

It has become a cliché to point to some long-standing feature of right-wing politics and conclude this is why Trump won. But it is also a point with a high degree of truth. Conservatives spent decades building a closed epistemology of alternative facts, and Trump repurposed it for his own ends.