Hoping Someone Else Fixes Everyone's Problem

Krasner says one problem with Gent's theory is that nations, unlike houses on a block, are not equals. Most countries lack the means to intervene, meaning that if powerful countries do nothing, nothing gets done. Domestic political pressures, he adds, make powerful countries unwilling to sacrifice lives: "That is why dealing with the tsunami was so nice -- no one got killed -- and why Clinton decided that the U.S. Air Force would fly at 30,000 feet when bombing to get the Serbs out of Kosovo."

Gent agrees that the extent to which countries care about what happens in other nations, and domestic politics, are factors in whether they intervene to stop a genocide.

And sometimes, he adds, countries take action even when no private interest is at stake, as the United States did in Haiti in 1994 when it restored democratically elected Jean-Bertrand Aristide to power. But Gent says the free rider model accounts for these phenomena, too.

"It could be the public good to you is worth more than the cost of intervention," he said. "If your interest in this country is so high you are willing to pay all the costs to get this public good for everyone, you will see unilateral intervention."

In other words, if the pothole is right in front of your house or poses a problem especially for you, you may be willing to fix the problem on your own. Small countries do step up to the plate -- when the problem is at their doorstep. African nations, not major powers, are the ones now sending peacekeepers to halt the killings in Darfur.

What it comes down to is a trade-off between what Gent calls salience -- the connection a country has to another country's problem -- and the cost of doing something. Problems in nearby countries, or in places that share historical or ethnic ties, are like the pothole in front of your house.

Difficult problems in distant lands such as Burma are like potholes way down the block. For such problems, the world simply clucks its disapproval and then does nothing.