There is, of course, a perfectly respectable argument for accelerating the transition from U.S. to Iraqi authority that has been laid out in recent days both by Defense Secretary Donald Rumsfeld on this page and by Ahmed Chalabi, member of the Governing Council and head of the Iraqi National Congress. American forces are not good at doing police work; the faster they can be replaced by Iraqi counterparts the less hostility they will generate on the part of the Iraqi people. We do not want to create a situation of dependency in which our nation-building efforts crowd out those of the locals and stifle their initiative. Mr. Rumsfeld is arguing in effect for nation-building "lite," the counterpart to his small-force approach to winning the war itself.

But there are also some very important reasons for not making the turnover too rapid or skimping on resources. Any new Iraqi provisional government will be very weak, both because it lacks depth in administrative skills and because it will have serious problems of legitimacy. The former problem can be fixed as more Iraqis are recruited and trained, and as former officials with skills are vetted for Baathist loyalties, but this takes time. The problem of legitimacy will presumably ultimately be dealt with as a new constitution is drafted and the first democratic elections are held, but this again is a matter of years rather than months. Members of the Governing Council working on the constitution have warned that meeting Colin Powell's six-month deadline for a draft document will hand power to the Islamists, since they are the best organized political force today. It is right to warn against long-term dependency, but dependence is often born out of genuine weaknesses that cannot be easily remedied.

It is very important to understand that nation-building involves a lot more than training indigenous police and military forces to take over their coercive roles from the occupying power. Unless such forces are embedded in a broader structure of political parties, civilian administration, respect for individual rights, and rule of law more generally, they are subject to being hijacked or abused in the internal struggle for power. The U.S. has unfortunately made this mistake in earlier nation-building exercises. The U.S. created a modern national guard in Nicaragua during its late 1920s intervention there, only to see that institution hijacked by the dictator Anastasio Somoza once the Marines left in 1932. Abuses in past decades by U.S.-trained police forces from Central America to Vietnam explain why there are legal restrictions currently in place limiting our ability to provide this kind of training.

As we proceed down the reconstruction road, there will be calls to declare victory and use that as an excuse for drawing down troop levels and capping resource transfers. We have seen these kinds of exit strategies before: At the end of "Vietnamization" we left South Vietnam's president Thieu hanging on for two years before being overwhelmed by North Vietnam in 1975.

The Bush administration has always been schizophrenic on the subject of how much effort to invest in nation-building. Last February, when addressing the American Enterprise Institute, the president said that the U.S. would stay in Iraq "as long as necessary, and not a day more." The first part of the phrase represents the neoconservative position; the latter that of the traditionalist conservatives. Both could agree back before the beginning of the war that Iraq should be attacked and disarmed, but now that this has happened the self-contradictory nature of the statement is increasingly clear.