Sanctions

President Barack Obama issued a warning to Iran on Sept. 25, following the revelation that it had concealed a uranium-enrichment facility: Tehran must acquiesce to nuclear inspections, or the U.S. might impose “sanctions that bite.” But his tough talk belied an open secret: most sanctions don’t. Attempts to economically isolate rogue nations are the leech treatments of international diplomacy–traditional cure-alls that rarely persuade obstinate leaders to change their ways.

Sanctions have been a weapon of choice at least since 432 B.C., when officials in Athens barred Megarian merchants from the city’s ports. The tactic backfired, helping trigger the Peloponnesian War, but it caught on–particularly in the U.S., which has applied sanctions dozens of times since World War I, targeting offenses from narcotics-trafficking to human-rights abuses. Sometimes the measures work well. The threat of U.N. sanctions defused a 1956 row over the Suez Canal, and economic restrictions helped derail South African apartheid and spur Libya to disavow terrorism after the 1988 Lockerbie bombing.

Still, a 2007 study of 174 attempts during the 20th century found that sanctions at least partially met their stated goals just 34% of the time. Critics argue that sanctions frequently strangle ordinary citizens instead of their ornery leaders–as in Iraq, where by many estimates hundreds of thousands of children died as a result of food shortages and inadequate medical care because of sanctions aimed at Saddam Hussein during the 1990s. Sanctions have a sound motive–to signal outrage or harm without force. But that doesn’t mean they’re effective.