In advocating a “mature” foreign policy, Stephen Walt proposes that the United States reverse many of the specific policies President Bush has pursued since coming to office four years ago. An early and outspoken critic of Bush’s decision to invade Iraq, Walt suggests that Washington pressure Israel to end and reverse its settlement policies, abandon the push for democratization in the Middle East, curtail its reliance on nuclear weapons as the best way to halt proliferation, and again embrace international institutions as a means of legitimizing American power.

But for all his differences with Bush on specific policies, what is most striking about Walt’s critique is the extent to which it rests on assumptions about the world that also inform Bush’s foreign policy. Walt, like Bush, believes international politics is primarily about the relations between states. Both believe power matters most in international affairs—and that the United States, as the most powerful country, must make preserving its power advantage the fundamental purpose of its foreign policy. And both believe that the American national interest is the only reliable guide to its foreign policy.

Moreover, while Bush’s rhetoric often suggests otherwise, the actual conduct of foreign policy in the past four years mirrors the offshore balancing strategy Walt advocates. Bush has pushed for a reduction in the American military presence in Europe and Asia along the lines Walt supports. He has largely ignored areas around the world that are deemed of only peripheral interest to the United States—Africa and Latin America foremost among them. He has embraced rather than antagonized America’s most likely global competitors such as China, Russia, and India, and he has sought to divide Europe to exert power rather than to unite it in possible opposition to American interests. And for all his democratization rhetoric, Bush has done very little to undermine the authoritarian rule of America’s most important friends in the Middle East.

Iraq, of course, is the glaring exception to Bush’s offshore balancing strategy. The decision to invade represented a major commitment of American military power with consequences that are growing more costly each passing day. But Iraq may be the exception that proves the rule. Having committed military force there, America is in no position to repeat this strategy elsewhere. And even Bush now appears to have learned that such commitments can be costly—which is why he stresses the importance of diplomacy in dealing with North Korea, Iran, and Syria.

In stressing the commonality between Bush’s foreign policy and Walt’s critique, we do not mean to defend Bush or his policies. To the contrary, both are deeply flawed—but so is Walt’s critique. What neither Bush nor Walt appear to understand is that we no longer live in a world of competing nation-states, where power is the coin of the realm. That was the age of Metternich; now we live in the age of the microchip—and we must have a foreign policy relevant to this new world rather than the old world we have left behind.

As far as America is concerned, the age of geopolitics has ended and the age of global politics has begun. Throughout the 20th century, traditional geopolitics drove American foreign policy—threats stemmed from particular regions of the world, and the overriding goal of American policy was to prevent any one country from achieving dominion over the Eurasian landmass. Today, in an era of unprecedented globalization and unparalleled American power, threats are no longer geographically centered or limited to hostile governments. Where we once stood apart from much of the world’s ills, today our prosperity, our health, and our security are increasingly shaped, even threatened, by developments far beyond our borders.

This new reality represents a profound change in America’s predicament. For much of our history, America’s leaders found it relatively easy to fulfill the first obligation of government—to keep us safe from foreign attack. For more than 180 years, geography and circumstance protected the United States. With the exception of the British in 1812 and the Japanese in 1941—and even then only briefly—no country had the capacity to penetrate America’s natural defenses. This changed in 1957 with the Soviet launch of the Sputnik satellite, which raised the specter of missiles raining on American cities. Soon, though, a combination of mutual deterrence, arms control, and limited defenses eased fears of that new threat to Americans’ lives.

Until September 11, 2001. Then a new reality dawned—the likelihood of foreign dangers reaching American soil are far greater than at any time in history. Terrorists can slip through porous borders and bring carnage to America. Nuclear materials and chemical agents can be shipped from distant places on containers into American harbors without much risk of ever being detected. Virulent diseases can emerge almost anywhere on earth and rapidly reach our shores. Rising global temperatures can trigger a catastrophic change in climate, potentially remaking the American economy and society. In short, the world, and many of its ills, have come to America.

Given the reality of an era in which threats are no longer bounded by geography and where America can no longer shield itself from the dangers of an unruly and unpredictable world, an effective foreign policy requires international cooperation to achieve many of America’s most basic objectives. Unfortunately, many of the most important international institutions are increasingly unable to ensure such cooperation. The United Nations suffers both from inadequate capacity and a legitimacy deficit. NATO may have the military capabilities, but is limited in its geographic and non-military reach.

The challenge for American foreign policy in the age of global politics therefore is to adapt existing international institutions and create new ones to ensure effective cooperation between the United States and its most important and capable democratic partners. It is a challenge neither Bush’s unilateralism nor Walt’s offshore balancing is likely to meet.