Today’s Washington Post features a very interesting article by Shankar Vedantam that reports on recent research by a pair of political scientists that examines why the Davids of the world tend to defeat the Goliaths and why the U.S. might need to reexamine its approach to military conflict:

Don’t Send a Lion to Catch a Mouse

Two centuries ago, Napoleon Bonaparte sent his armies into Spain to overthrow a monarch who had once been a French ally. Napoleon, who believed he was touched by the hand of destiny, predicted his troops would be welcomed as liberators by ordinary Spaniards. He was wrong. The resulting Peninsular War from 1808 to 1814 seriously undermined French prestige, handed Napoleon a stinging defeat and produced a raft of unanticipated consequences that included the outbreak of deadly civil wars.

Historians would have a field day exploring parallels between Napoleon’s Peninsular War and President Bush’s war in Iraq, but that is not where we are going today. The Peninsular War interests us because it is one of the earliest examples of an asymmetrical war — Spanish insurgents faced down the powerful French army by using stealth, deception and the support of civilians. It is the war that gave us the term “guerrilla.”

Two political scientists recently examined 250 asymmetrical conflicts, starting with the Peninsular War. Although great powers are vastly more powerful today than in the 19th century, the analysis showed they have become far less likely to win asymmetrical wars. More surprising, the analysis showed that the odds of a powerful nation winning an asymmetrical war decrease as that nation becomes more powerful.

The analysis by Jason Lyall at Princeton University and Lt. Col. Isaiah Wilson III at the U.S. Military Academy at West Point shows that the likelihood of a great power winning an asymmetrical war went from 85 percent during 1800-1850 to 21 percent during 1950-2003.

The same trend was evident when the researchers studied only asymmetrical conflicts involving the United States. The more industrialized a powerful country becomes, the more its military becomes technologically powerful, the less effective it seems to be in an asymmetrical war.

Essentially, what Lyall and Wilson are saying is that if you want to catch a mouse, you need a cat. If you hire a lion to do the job because it is bigger and stronger, the very strength and size of the lion can get in the way of getting the job done. [full text]