While many political pundits have been thrown into a tizzy by Donald Trump’s unexpectedly strong and robust popularity as a GOP candidate, none have been quite so addled as Weekly Standard editor William Kristol, who in the space of two months has gone from being Trump-curious, to being anti-Trump, to now becoming, in his own words, “anti-anti-Trump.”

When Trump first entered the race, Kristol welcomed him as a fresh voice who was energizing Republicans, and warned the GOP establishment against being openly dismissive of the billionaire reality show star. “It's very, very foolish if the Republican establishment or the Republican candidates treat him with disdain instead of saying, you know what, good to have more voices, good to have some unconventional voices in the race,” Kristol told radio host Steve Malzberg on July 7. But when Trump suggested that John McCain was not a real war hero because he had been shot down and captured, Kristol—who had long been an avid McCain partisan—turned on Trump. On July 19, on ABC’s This Week, Kristol unloaded on Trump, saying, “he was a controversial character who said some useful things, I think, and brought some people into the Republican tent. But he jumped the shark yesterday. He's dead to me…. I mean, he insulted every veteran … with these insane statements about how it's your fault that you're captured or shot down…. So I'm finished with Donald Trump. And I don’t think it's going to—he'll—and I don't think—I don't think he'll stay up in the polls, incidentally.”

Kristol then went through a phase of constantly and incorrectly predicting Trump’s imminent demise, saying on nine separate occasions that we had hit “peak Trump.”

But now that it's clear he was wrong about Trump's staying power, Kristol is articulating an “anti-anti-Trump position.” As Kristol explained in a series of tweets on August 20,I remain not pro-Trump, but I'm once again drifting into the anti-anti-Trump camp.” Kristol’s feelings about Trump have been going up and down like a yo-yo. How do we explain that?

One answer is in some family history. In 1952, the late Irving Kristol, William Kristol’s father, published an inflammatory article in Commentary magazine which offered an ambiguous account of the anti-Communist crusader Joseph McCarthy. While the elder Kristol acknowledged that McCarthy was a demagogue, he also thought that liberal critics of the red-baiting senator were worse. In outlining his anti-anti-McCarthy position, Irving Kristol wrote, “For there is one thing that the American people know about Senator McCarthy: He, like them, is unequivocally anti-Communist. About the spokesman for American liberalism, they feel they know no such thing.”

Irving Kristol’s partial defense of McCarthy was hugely polarizing. As Commentary editor Norman Podhoretz would recall in his 1967 autobiography Making It, the “notorious” article made Kristol “for a while the most controversial figure in New York.” In philosophic terms, Kristol, in the manner of the political theorist Carl Schmitt, was setting up a basic friend-enemy distinction, allying himself (and the American people) with McCarthy against cosmopolitan liberals, seen as inherently untrustworthy.

In a 2003 editorial for The Weekly Standard, William Kristol echoed his father’s words to defend Bush’s foreign policy: “But the American people, whatever their doubts about aspects of Bush's foreign policy, know that Bush is serious about fighting terrorists and terrorist states that mean America harm. About Bush's Democratic critics, they know no such thing.” The same basic friend-enemy binary undergirds these words, which are also echoed in William Kristol’s recent anti-ant-Trump tweets: “So much of the sniping at him misses the point. Much of the criticism of Trump has the feel of falling (fairly or unfairly) into the hobgoblin-of-small-minds category. Trump's appeal is that he seems to speak unhesitatingly for America and against our enemies, rivals and threats to our well-being.”

William Kristol’s filial loyalty might be endearing if they were put in the service of a better cause than defending a demagogue and libeling Democrats as anti-patriotic. But something more can be said about the parallels between how the two Kristols supported McCarthy, Bush, and Trump.

Irving Kristol’s partial defense of McCarthyism was rooted in fear. As the historian Peter Novick noted in his 1999 book The Holocaust in American Life, the strident anti-Communism that Commentary magazine adopted in the early 1950s was rooted in no small part by a fear that demagogues like McCarthy might try to smear American Jews as pro-Communists. As Podhoretz himself observed, the editorial line of Commentary at the time Irving Kristol’s article was published was guided by “a secret program to demonstrate that not all Jews were Communists.” (Podhoretz was a Commentary contributor at the time and close to the staff, although he didn’t assume editorship until 1960). Irving Kristol had an extra reason to fear McCarthyism given his radical past as a youthful Trotskyist in the 1940s.

So Kristol’s anti-anti-McCarthy stance sprang from not just a shared anti-Communism with McCarthy but also the fear that the McCarthyite mob might turn against himself personally, as someone who was Jewish. Might a similar fear of Donald Trump lurk in his son’s mind? Trump is not afraid to attack conservative establishment figures like Jeb Bush and Megyn Kelly all while riling up the right-wing base with xenophobia. Trump has also not been shy about bullying Kristol, referring to The Weekly Standard as a “small and slightly failing magazine.”

In 1952, Irving Kristol wanted to make sure the McCarthyite mob didn’t go after him. In 2015, William Kristol is trying to keep the Trumpite hordes at bay, appeasing them with his anti-anti-Trump position so they don’t turn their ire against him. The task of standing up to McCarthy was left to people other than Irving Kristol, just as the fight against Trumpism will have to be waged without the help of William Kristol.