When Megan McArdle poses the question, "To fight or not to fight?" she hypothesizes that the answer largely rests on whether the United States opts to involve itself in a foreign intervention. Without American participation, she contends, "no one else is going to do it for us--the African Union cannot make peace in Darfur, none of Iraq's neighbors can help it if it erupts into civil war, and so forth."

To this Matthew Yglesias adds the much-needed caveat that the participation of other countries in foreign interventions can in fact add value in terms of both military effectiveness and political legitimacy. He also rightly cautions that this argument -- that American initiative is the only way to mount a serious intervention -- can dangerously provide cover for a more naked unilateralist streak.

I would add the important reminder that not all "fighting" is equal, and, more significantly, that not all interventions must amount to combat. War-fighting, counter-insurgency, and peacekeeping are, just to name a few, all very different phenomena that each operate according to very different rules and whose effectiveness require very different types of involvement. To McArdle's example that "the African Union cannot make peace in Darfur," then, the obvious answer is of course not. The peacekeeping force in Darfur is exactly that: a peacekeeping force. Peace does not come at the barrel of a gun -- least of all at the barrel of an American gun -- and the only ones that can make peace, unfortunately, are the parties at war themselves.

This does not mean that the U.S. and other countries have no role to play in such peacebuilding situations. Rather, these type of scenarios demand, if anything, more multilateral involvement, as international diplomatic pressure -- particularly from neighboring countries with a stake in stabilizing their region -- will go a lot farther in pressing for a peace accord than will American troops.