Managing the peace in Iraq may become a more daunting task than running the war. Even as U.S. troops prepared their assault on Baghdad, the need grew more urgent for coalition leaders and their disgruntled allies at the United Nations and NATO to consider putting in place an administrative structure to run Iraq.

The ultimate goal is to fashion postwar Iraq as a democratic nation- state made up of three semiautonomous ethnic cantons resembling, at best, Switzerland. A botched effort, however, could turn Iraq into a festering version of Lebanon's internecine mess. So it's imperative that coalition planners get it right and not waste too much time doing it.

Underscoring this need is the realization that the best possible outcome of the battle for Baghdad - a quick victory and an implosion of Saddam Hussein's regime - could generate instant civil chaos unless the coalition is prepared to keep the peace in the areas it conquers and run basic functions like public health, sanitation, food distribution and power generation.

It has become increasingly clear that the UN and, very likely, NATO will play significant roles in postwar Iraq. The urgency to define their roles was behind the round of meetings with European foreign ministers that Secretary of State Colin Powell held Thursday. The meetings, unsurprisingly, showed deep splits paralleling the acrimonious UN debate over the war.

Europeans, chief among them France, think that a lengthy U.S. occupation, with Washington taking the primary role in shaping Iraq's reconstruction, would stoke anti-American sentiment around the globe and - perhaps more to the point - prevent other nations from participating in the rebuilding and profiting from it. Powell argued that those who fought and paid in lives and treasure should have the biggest say when the war is over. But, Powell said, Washington is now amenable to the UN playing a significant, if not the primary, role. Just as important, Powell suggested that allies were receptive to the idea of NATO peacekeeping after the war.

The disagreements are over process, not over the goal in Iraq. There is a broad and sensible consensus for what Iraq should look like and what its government should be. Ideally, after a short period of military occupation and UN administration, Iraqis would form a type of federal central government with limited powers over three distinct ethnic cantons or states - a Kurdish state in the north, a Sunni state in the center, and a Shiite state in the south. Each state would be able to govern itself except for sovereign national functions like central banking, defense and foreign relations, which would be assumed by a central government in Baghdad. The individual states would be represented proportionally in a parliament. The goal is to keep Iraq together as a sovereign nation, but to allow ethnic and religious autonomy within. What would make this feasible is the geographic contiguity of the three main groups - much like Switzerland's cantons.

Of course, between the ideal and the possible lies a wide gulf. Best to start negotiating soon.