During the Cold War, the North Atlantic Treaty Organization (NATO) was the West's line of defense against possible Soviet aggression. But the end of the Soviet Union in 1991 and the disappearance of NATO's communist equivalent -- the Warsaw Pact -- raised doubts about NATO's relevance. Nearly 20 years later, the specter of obsolescence still hangs over the venerable 26-nation alliance. So-called "Atlanticists" in both the United States and Europe say NATO's role in keeping the United States tied strategically to Europe justifies the alliance's continued existence. Moreover, NATO makes Moscow uneasy, and that's a good thing, they say. Others feel NATO should "earn its keep" by assuming new military responsibilities, such as protecting global energy-supply routes. But one thing is certain: It's not your grandfather's alliance. Since the 1990s, nearly a dozen former Soviet states and Soviet-bloc nations have joined NATO, easing their transition to democracy. NATO also has expanded its operations beyond Europe to Afghanistan, which may become the 60-year-old alliance's ultimate testing ground.

Roland Flamini is a Washington-based correspondent who writes a foreign-affairs column for CQ Weekly. Fluent in six languages, he served as Time magazine's bureau chief in Rome, Bonn, Beirut, Jerusalem and the European Common Market and later served as international editor at United Press International.