BY GEOFFREY GARRETT

Historians may well come to look back on the 18 months from Sept. 11 to the Iraq war as fundamentally realigning the tectonic plates of world politics.

In the 1990s, “more markets” was the preferred solution to most problems as traditional security concerns slipped down the global agenda. The United States stood unchallenged as a global power, but it exercised its power largely through multilateral economic diplomacy. Today, security concerns are again preeminent, the heady days of globalization seem long gone and multilateralism is in question. The new global epoch will be defined not by struggles among great powers, but rather as a response to threats to powerful countries from small authoritarian states and non-state actors with access to weapons of mass destruction. What remains unclear is the form this response will take.

From his position of global leadership, President Bush has implicitly challenged two organizing principles of international politics. First, his administration has expanded the legitimate justifications for the use of force. The war against the Taliban was consensually viewed as legitimate retaliation against the attacks of Sept. 11. The National Security Strategy’s doctrine of preemption went further to justify the destruction of an imminent threat of attack before it is launched. Now the war against Iraq apparently goes still further to justify war as prevention — the eradication of a threat to the national interest even before the perpetrator has the capacity effectively to carry it out.

Second, the Bush administration has been willing when necessary to ignore the collective security principles of the United Nations and NATO. In marked contrast with the strenuous efforts of Presidents George H.W. Bush and Bill Clinton to enmesh American hegemony in multilateral institutions, President George W. Bush has been willing to stay on the outside (the Kyoto Protocol, the International Criminal Court) and to act independently (with respect to the U.N. Security Council).

In expanding the definition of legitimate uses of force and eschewing multilateralism, the Bush administration has incurred several major risks. Preemption and prevention may provoke radical Islam to try to inflict more damage on the United States and the West. Independence of action jeopardizes the Atlantic alliance that has been solid and successful since WWII. Given the American public’s long-standing ambivalence to expansive internationalism, the Bush administration also risks alienating its own electorate should its policies be seen to fail.

Sept. 11 emboldened the Bush administration to take these risks. The abstraction of national security has become the reality of personal security for all Americans; their tragedy was greeted with sympathy and empathy around the world. Sept. 11 created a deep well of political capital for the Bush administration. But the well could run dry — at home and abroad — if the war in Iraq is long and if casualties among coalition soldiers and Iraqi civilians are high.

There are two opposing scenarios as to how the war might play out. In the “liberation” scenario, Iraqi soldiers will lay down their arms and Iraqi citizens will celebrate in response to the coalition’s attack on Saddam Hussein’s regime. In the “quagmire” scenario, Iraqi soldiers will take off their uniforms and, aided by Iraqi civilians, will engage the coalition in urban guerrilla warfare.

The closer the war reflects the liberation scenario, the more justifiable will be the risks taken by the Bush administration. Rebuilding Iraq through the U.N. could simultaneously repair the Atlantic alliance. Arabs might come to thank the United States for removing a long-standing thorn in the side of peace and progress. The United States’ would-be attackers could be chastened by a graphic display of American military might. And at home, the administration could receive hearty fillips in the form of soaring popularity and stock prices. But all of these depend upon a relatively quick and painless war.

As of March 30, it remained unclear whether the war will last weeks or months. Extreme versions of the liberation scenario have been exposed as either bad intelligence or blinkered ideology. But it is far too early to subscribe to the quagmire scenario. We can only hope that the war plays out with a minimum of casualties, not only in Iraq but on the global political stage as well.

Garrett is vice provost of the UCLA International Institute.