I see that Todd Gitlin—prolific author, former president of Students for a Democratic Society, disgruntled academic radical—has died, age 79. Gitlin was a curious figure. He was indisputably a man of the Left. But he spent much of his career lamenting the many ways in which the Left had disappointed him. Gitlin’s most famous book was undoubtedly “The Sixties: Years of Hope, Days of Rage” (1987), his paean to a radical Left he could warm up to. But by the mid-1990s, the hope had palled and the rage had become a parody. In “The Twilight of Common Dreams: Why America is Wracked by Culture Wars” (1995), Gitlin lambasted various “ideologues of the Right” for perpetuating a Cold War mentality after the raison d’être for the Cold War—the Soviet Union—had disappeared. But he was also critical of a radicalism that, to his mind, had lost its way. Gitlin was a canny …