THE PUBLIC AND THE WAR….Over at Foreign Affairs, the burning question of the day is why public support for Iraq has fallen so precipitously. John Mueller, a scholar of war and public opinion, says the answer is simple:

American troops have been sent into harm’s way many times since 1945, but in only three cases ? Korea, Vietnam, and Iraq ? have they been drawn into sustained ground combat and suffered more than 300 deaths in action. American public opinion became a key factor in all three wars, and in each one there has been a simple association: as casualties mount, support decreases.

The White House begs to differ. As the New York Times reported on Sunday, they figure the public is OK with casualties as long as victory is in sight, a view that originated with Peter Feaver, a Duke University political science professor who joined the NSC staff in June. Today, Feaver’s research partner, Christopher Gelpi, takes to the pages of FA to defend their position.

Unfortunately, the result is a mess, and as near as I can tell the reason is simple: with only three wars to work with, and one of them with scant polling data, there’s just not enough information to draw any firm conclusions. What’s more, public opinion is so delicately sensitive to question wording that even for Vietnam and Iraq it’s hard to tease out trends with any reliability. Gelpi, in an effort to fix this, actually makes things worse by trying to use presidential approval as a proxy for approval of the war:

From July to November 2003, there were 200 U.S. deaths in Iraq and the president’s approval rating dropped by more than eight percentage points. On the other hand, from July to November 2004, there were 300 deaths, but Bush’s approval rating remained unchanged.

This doesn’t stand up to a moment’s scrutiny. Not only is presidential approval the result of a lot more than just the state of the war, but Gelpi fails to note that July-November 2004 was right in the middle of a presidential campaign. The best conclusion to draw from this data is probably that public opinion can be temporarily turned around if you’re in the middle of a viciously partisan campaign and willing to spend hundreds of millions of dollars on slick advertising aimed solely at boosting the president’s poll numbers. As soon as it stops, though, you’re doomed.

Given the paucity of the data, it’s a little hard to take this debate seriously. Common sense, after all, suggests that both explanations are true: support for war does decline as casualties mount, but the rate of decline also depends on whether the public believes in the war and believes that its casualties will eventually bring us victory. Proving it, though, will take a lot more than looking at a bit of thin and unreliable polling data.