He may have been the least-fetching model ever to grace the cover of Esquire. But when Irving Kristol—essayist, editor, professor—appeared on the Feb. 13, 1979, edition of the venerable men's magazine above a headline that read "Godfather of the Most Powerful New Political Force in America," the distinction was well deserved. Within a year and a half, the movement that Kristol had launched in the late 1960s—a haven, he said, for disaffected ex-liberals like himself who'd been "mugged by reality"—would help propel Ronald Reagan to the presidency, and it would remain the dominant strain in American politics through the war in Iraq a quarter century later. All ideologies eventually fall out of favor, especially in a city as fickle as Washington. What distinguished Kristol, the husband of historian Gertrude Himmelfarb and father of conservative columnist William Kristol, was his eagerness to engage anew with a world that was constantly changing around him. In the wake of World War II, he rejected the radical socialism of his youth and became a leading anticommunist; amid the foment of Vietnam, he charted a course between the isolationism of the antiwar left and the libertarianism of the Goldwater right. Through it all—the years at Commentary, New York University, the American Enterprise Institute, and The Wall Street Journal—he maintained his wit, good cheer, and grace. May he be a model to the pundits and politicians whose careers he made possible.