Krugman’s flip-flop—from a denigrator of “crazy conspiracy theories” to an eager promoter of them—exposes perhaps just how fragile the political psyche of modern American liberalism is. The current American Left—the most prominent set of politicians, pundits, writers and academics working today—was forged in the fire of the Bush years, for the Left a time of paranoia, nonstop anger, smug self-righteous back-patting and intellectual balkanizing. These tendencies have been present among progressives for decades, of course, but it is hard to overstate just how much George W. Bush exacerbated them. Prominent among these liberals, of course, is Paul Krugman, who was a constant, sneering critic of both Bush and Republicans more generally during those years.

The election of Barack Obama allowed the Left to channel these behaviors proactively rather than reactively: instead of screaming every time George Bush blinked, or holding anti-war protests in a desperate attempt to recapture the Yippie magic, they could apply all the moral preening and political posturing in an active way. They did this for eight years, and though they had varying degrees of success due to oppositional congressional majorities, they had the presidency at the very least. (For good measure, they constantly kept alive the specter of George Bush, blaming him for virtually all of the nation’s problems even after two terms of his successor.)