In his contribution to The Short American Century: A Postmortem reviewing the pragmatic realist tradition, T.J. Jackson Lears discusses Kennan’s conservatism:

Though he did not share Niebuhr’s belief in original sin, Kennan did acknowledge the tragic limitations of all human striving. Man, he wrote in his last book, Around the Cragged Hill (1993), was a “cracked vessel,” whose imperfections would always curtail and confound his aspirations. So the mature Kennan rejected “all messianic concepts of America’s role in the world…[all] prattle about Manifest Destiny and the American Century.” The teleology of empire was unsupported by evidence: “I know of no reason to suppose,” Kennan wrote, “that ‘democracy’ along western European or American lines is necessarily, or even probably, the ultimate fate of all humanity.” He noted the improbability of achieving noble ends by employing ignoble means. He questioned open-ended commitments to vague abstractions like “human rights.” He distrusted the ideology of progress, which sanctions all sorts of mischief in the name of human betterment. Unlike Barry Goldwater or Ronald Reagan, he could genuinely claim allegiance to conservative tradition. (p.109-110)