George Kennan was the father of cold war foreign policy. Which isn’t to say that the author of the famous “long telegram”—which argued against postwar chumminess and in favor of containment as a basis of U.S. strategy—was always a proud papa. As containment became the rationale for an arms race, third-world proxy wars, and American involvement in Vietnam, the ex-diplomat became a leading academic voice for realism, calling on Washington to pipe down about the glories of multinational institutions and the centrality of human rights. The tension in his work helps explain why, 20 years after the USSR’s demise and six years after Kennan’s own death at age 101, he remains a source of intense debate and the subject of a popular new biography. One critic once explained that Kennan understood Russia but not the United States. Your take on the latter country, no doubt, will influence your reactions when biographer John Lewis Gaddis speaks this afternoon.

Gaddis discusses his book at 3 p.m. at the Woodrow Wilson International Center for Scholars, 1 Woodrow Wilson Plaza, 1300 Pennsylvania Ave. NW. Free. wilsoncenter.org. 202-691-4000.