In the wake of revelations that Iran had concealed a secret uranium-enrichment facility near the holy city of Qum, the U.S. began working international back channels to gauge support among its allies for a fresh round of sanctions against Tehran. While the U.S. and U.N. have sanctions in place against the Iranian finance sector as well as travel and trade restrictions, Secretary of State Hillary Clinton said the Obama Administration was investigating how to "broaden and deepen" the measures, while Defense Secretary Robert Gates noted the menu of potential punishments was a "pretty rich list to pick from" including the suspension of investments in the Iranian oil and gas industries and tighter restrictions on Iranian banks.
In a muscle-flexing response, Tehran announced that its Revolutionary Guards had conducted new tests of medium- and short-range missiles a sign that the threat of further sanctions didn't seem to have made much impact. For one thing, Iran has been dealing with such restrictions since the Islamic revolution in 1979. For another, Iranian President Mahmoud Ahmadinejad is probably in on the open secret about economic sanctions: they don't really work. Attempts to economically isolate troublemaking nations are the leech treatments of international diplomacy: traditional cure-alls that, though well-intentioned, rarely force regime change or prompt significant policy shifts, particularly when done unilaterally and often a greater hardship for the citizens living under these regimes than for the leaders.
The first known use of economic sanctions took place in 432 B.C., when Athenian officials, irked by the assistance the Greek state of Megara had afforded its rivals in Corinth, banned Megaran merchants from its ports. The move didn't go over very well instead of reasserting Athenian supremacy, it helped trigger the 27-year-long Peloponnesian War, which ultimately stripped Athens of its empire. But the tactic caught on. Venice imposed sanctions against Bologna in 1270 in order to coerce them into buying their wheat instead of grain from Ravenna, and in subsequent centuries, the Hanseatic League tried trade bans against foreign adversaries like the Russian principality of Novgorod.
Actual warfare has become infinitely more costly in recent generations as the bloody conflicts of the 20th century proved. Thus sanctions, by and large, have become war by other means. The U.S. has applied such measures more than 100 times since World War I, against more than 75 countries. President Franklin D. Roosevelt imposed them as a check on Japanese imperialism in 1940, Ronald Reagan leveled them as a way to combat martial law in Poland, and a legion of leaders have used sanctions in recognition of the atrocities perpetuated in Saddam Hussein's Iraq, Kim Jong Il's North Korea and Burma under the military junta.
The practice has had some successes: President Dwight D. Eisenhower defused a row over the Suez Canal with economic sanctions against Britain; Swiss banks were forced to pay reparations to Holocaust survivors when faced with a boycott, led by some U.S. states, for harboring pilfered assets; and stiff sanctions helped convince Libya to disavow terrorism after the 1988 Lockerbie jetliner bombing. But those are generally the exceptions. "Putting a sanction on a country always seems to be an inexpensive way to address the problem," Senator Richard Lugar of Indiana has said. "Unfortunately, almost none of these sanctions have brought about change." That's particularly the case when they’re leveled unilaterally. A 1997 study by the Institute for International Economics found that since 1970, unilateral U.S. sanctions met their stated goals less than 20% of the time, while costing the U.S. at least $15 billion annually in projected export revenues.
Sanctions can also strangle ordinary citizens instead of obstinate world leaders. More than 1 million Iraqi civilians died from starvation and inadequate medical services as a result of measures imposed against Saddam in the 1990s, according to some estimates.
So far, it's unclear how deeply a new batch of sanctions against Iran would cut, particularly since the U.S. needs Moscow and Beijing as signatories if it wants the initiative to pack a punch. Russia and Iran have shared economic interests, and according to some estimates, China has some $100 billion tied up in Iranian oil and gas reserves. Both countries have been unwilling to rebuke their strategic partner in the past. A watered-down set of sanctions might be disappointing to those, like Israeli Prime Minister Benjamin Netanyahu, who want to "cripple" Iran. But they wouldn't be out of the ordinary; the U.S. has punished countries for everything from harboring terrorists to mistreating animals. "Sanctions may not do much to the so-called enemy, but they do feel warm to those imposing them," wrote Britain's Independent in 2007. Still, if shaming Iran and expressing outrage is the primary purpose of the exercise, the U.S. could always make Ahmadinejad wear a dunce cap.