My Council on Foreign Relations colleague Stephen Biddle makes an excellent point in this Washington Post article. He cautions against concluding that, because American forces have had greater success recently in pacifying Iraq, they can be pulled out with impunity.

At best, as Steve notes, Iraqis will observe a fragile truce in the years ahead. Even if terrorism continues to fall, distrust among the various sectarian and ethnic groups will continue to run high. In such a situation, maintaining the peace requires the presence of a trusted outside force that can be seen as a neutral arbiter of intercommunal disputes and protector of each side against the other.

In Bosnia and Kosovo, that role has been played since 1995 and 1999, respectively, by NATO forces. In Iraq, there is scant prospect of other countries dispatching peacekeeping forces, at least not until the situation becomes a lot less violent than it is even today. Many of our remaining allies (the Poles, Brits, and Australians) are already pulling their forces out. That leaves the U.S. military as the only possible long-term peacekeeping force.

“The troop counts normally sought for peacekeeping are not much lower than those for counterinsurgency war fighting, at least in the early years, and a meaningful outside presence can be needed for a generation,” Biddle writes.

He’s right. And it would be a good thing if President Bush, the various presidential candidates, and Congressional leaders started talking more publicly about the need for this kind of generational commitment. As Steve notes, “If we are not prepared to stay in large numbers for a long time, the gains of recent months could easily be reversed.”