Caveats aplenty — the data didn’t include Baghdad, there’s no way to tell if attacks increased because of the rhetoric or were just re-timed to coincide with it — but to no one’s surprise except possibly the left’s, “U.S. out of Iraq” does indeed create an incentive for jihadis to try to push the U.S. out of Iraq.

Are insurgents in Iraq emboldened by voices in the news media expressing dissent or calling for troop withdrawals from Iraq? The short answer, according to a pair of Harvard economists, is yes…

The paper “Is There an ‘Emboldenment’ Effect in Iraq? Evidence From the Insurgency in Iraq” concludes the following:

* In the short term, there is a small but measurable cost to open public debate in the form of higher attacks against Iraqi and American targets.

* In periods immediately after a spike in “antiresolve” statements in the American media, the level of insurgent attacks increases between 7 and 10 percent.

* Insurgent organizations are strategic actors, meaning that whatever their motivations, religious or ideological, they will respond to incentives and disincentives.

The actual study is behind a reg wall so I can’t tell if it addresses whether there’s some “optimal” level of war criticism beyond which attacks spike sharply or if it’s a steady upward slope starting from zero. I know which way the comments on this post are going to go, but keep this in mind: If the propriety of anti-war rhetoric turns on whether it makes the mission in the field harder, then arguably the same is true of Geert Wilders’s film. The Secretary General of NATO has said that explicitly, in fact, as has one of the U.S. military’s joint task forces in Afghanistan. If an economist can prove that criticism of Islam increases attacks (which shouldn’t be hard), you want to roll that back too?

Exit question one: Will the media report on this rather media-unfriendly finding? Exit question two: Does this create any incentive for the press to at least include more pro-war voices in its coverage? “No, the media isn’t an instrument of the military” vs. “Yeah, since they’re politically inclined to exclude pro-war voices as it is.” And exit question three: What’s the effect of less Iraq coverage? Does that reduce the number of attacks, which in turn reduces the coverage, which in turn reduces the attacks in a glorious virtuous circle, or is there no effect?

Update: The paper’s publicly available here. Look for the link near the bottom.

Update: Bill Ardolino, who’s embedded twice with the Marines in Fallujah, comments below:

A source of mine is an official who focuses on Sunni insurgency. He was meeting with a Sunni tribal leader and the guy said to him, “We are with you on your upcoming attack on Iran!” The American goes, “We aren’t necessarily going to attack Iran.” And the Sunni responds, “Of course you are, we read it in an article by Seymour Hersh!”

Sunnis I spoke said they were mistaken about thinking we were “after the oil” when they first fought us. Much of what they saw along those lines was in the Arab media, but they pay attention to Western media as well. And they give special credence to criticism of America by Americans. It’s a fact.