Reconsidering the more troops in Iraq counterfactual

Via Crooked Timber, Mathew Yglesias and Sam Rosenfeld consider the agrument that the Iraq war was a good idea that was botched in its execution and find it wanting.

So was the Iraq War a good idea, ruined by poor implementation? Perhaps the founding myth of the incompetence argument is that the postwar mess could have been avoided had the United States deployed more troops to Iraq. “Army Chief of Staff General Eric Shinseki was ridiculed for suggesting that it would take several hundred thousand troops to secure Iraq,” wrote Senator Joe Biden in a June 2004 New Republic article. “He looks prescient today.”

Shinseki’s ballpark numbers were based on past Army experience with postconflict reconstruction. A RAND Corporation effort to quantify more precisely that experience, frequently cited by dodgers, concluded that a ratio of 20 foreigners for every 1,000 natives would have been necessary to stabilize Iraq.

The flaw in the popular “more troops” argument is strikingly easy to locate. The 20-to-1,000 ratio implies the presence of about 500,000 soldiers in Iraq. That’s far more than it would have been possible for the United States to deploy. Sustaining a given number of troops in a combat situation requires twice that number to be dedicated to the mission, so that soldiers can rotate in and out of theater. As there are only 1 million soldiers in the entire Army, a 500,000-troop deployment would imply that literally everyone — from the National Guard units currently assisting with disaster relief on the Gulf Coast to those serving in Afghanistan, Korea, and Europe to the bureaucrats doing staff work in the Pentagon and elsewhere — would be dedicated to the mission. This is plainly impossible. . .