“America’s Crisis of Legitimacy” by Robert Kagan, in Foreign Affairs (Mar.–Apr. 2004), 58 E. 68th St., New York, N.Y. 10021.

Americans may be from Mars, and Euro­peans from Venus, as Kagan asserted in a controversial article and subsequent book, Of Paradise and Power (2003), but it turns out that for best results in ventures such as the preventive war in Iraq, the Martians need Venusian backing. “There are indeed sound reasons for the United States to seek European approval,” he writes. “But they are unrelated to international law, the authority of the [UN] Security Council, and the as-yet nonexistent fabric of the international order.”

Though the Iraq war and the George W. Bush presidency “may have deepened and hardened the transatlantic rift into an enduring feature of the international landscape,” Americans and Europeans were already diverging in their views on international law and “what confers legitimacy on international action,” writes Kagan, a senior associate at the Carnegie Endowment for International Peace. Today, for the first time since World War II, most Europeans “doubt the legitimacy of U.S. power and of U.S. global leadership.”

Though Europeans demand that the United States win international backing for ventures such as the Iraq War, Kagan thinks that’s largely a smoke screen. Euro­peans didn’t look upon the Security Council as “the sole source of international legitimacy” during the Cold War, and they joined the United States in Kosovo in 1999 without the council’s sanction and in violation of “the sovereign equality of all nations, the bedrock principle of international law.”

The real issue is European influence over U.S. policy. During the Cold War, European influence was guaranteed by the fact that the protection of Europe itself from the Soviet Union was the paramount U.S. strategic goal. All that has changed.

Yet there’s still an important link. The United States “is and always has been a revolutionary power,” Kagan believes, a force for liberalism and democracy around the world. And that’s the real reason it needs the legitimacy that only Europe can provide: “The world’s sole superpower needs to demonstrate that it wields its great strengths on behalf of its principles and those who share them.” The Amer­ican people won’t indefinitely support efforts abroad “in the face of constant charges of illegitimacy by the United States’ closest democratic allies.”

Yet if the United States is to grant Europe influence over its exercise of power, possibly through the North Atlantic Treaty Organization, there must be agreement on “the nature of today’s global threats and the means to counter them,” warns Kagan. Such agreement doesn’t currently exist. Most Europeans think that the United States has exaggerated the risks of terrorism and weapons of mass destruction.

Kagan says it’s time for “the wisest heads in Europe” to ask themselves if they really want to bet that “the risks posed by the ‘axis of evil,’ from terrorism to tyrants, will never be as great as the risk posed by the American leviathan unbound.”