Because President Barack Obama’s attempt to entice Iran to give up its nuclear program has ended in unsurprising failure, he is now trying to ratchet up the pressure on the regime by leading the drive to increase international economic sanctions. However, even if he were to succeed in getting Russia and China to go along in the United Nations Security Council, the measures would probably be unsuccessful in achieving their stated goal.

The history of economic sanctions illustrates that they can be simultaneously successful and yet not very effective. Sanctions are usually successful in the country or countries that impose them. They are used to demonstrate more resolve to a recalcitrant country than a diplomatic slap on the wrist, but don’t go as far as covert action or a military attack. Sanctions are the middle ground of protest when diplomacy is perceived as too weak and covert action and military action are perceived as too dangerous or excessive. They also satisfy domestic political constituencies who are demanding action.

Unfortunately, however, the economic and political effects of economic sanctions on the target country rarely achieve their often-lofty goals. Sanctions, if severe enough, can bite economically by cutting off trade and financial transactions—for example, the most multilateral and comprehensive sanctions in world history against Saddam Hussein’s regime before the first Gulf War to attempt to dislodge the Iraqi invaders from Kuwait. Yet over time, history shows that cheating on sanctions increases dramatically as it becomes profitable for companies and countries to get top dollar for evading the restrictions on commerce. Thus, in the long term, the real economic effect is to merely raise the cost of trade and financial transactions to the target country.

These increased costs do punish the target nation, but do sanctions usually achieve their intended political goal? Again, the Iraqi case is illustrative. Even in the extreme case of grinding (at least in the short and medium term) worldwide and comprehensive sanctions, Saddam Hussein refused to leave Kuwait until he was evicted by military force. Furthermore, this goal of sanctions was more modest than demanding that the target country abandon a nuclear program, which is perceived as vital to its security, or even trying to achieve regime change.

And in the case of Iran, it is unclear which of these two more ambitious goals the multilateral, but incremental and selective, sanctions are intended to achieve. The three prior selective rounds of multilateral sanctions were directed toward the objective of getting Iran to halt the enrichment of nuclear fuel. Yet restricting more and more Iranian scientists from traveling abroad and exhorting countries to cut off trade with Iran will hardly achieve this ambitious goal. Lately, however, Secretary of State Hillary Clinton has accused the Iranian Revolutionary Guard military force of turning Iran into a military dictatorship and talked about an even more grandiose goal for any incremental increase in multilateral sanctions—undermining this heart of the regime.

The history of sanctions indicates, however, that surgically targeting the regime, while avoiding harm to innocent people, is almost impossible. The regime usually redirects the pain of sanctions away from the security forces and onto the backs of ordinary citizens (as Saddam Hussein did), causing a “rally around the flag” effect against the sanctioning nations. At a time when the autocratic rule in Iran is weakening because of election protests, the United States and the international community should be careful about giving the Iranian government an external threat against which to rally domestic support.

Because Russia and China, with substantial commercial connections to Iran, always drag their feet on further sanctions against Iran, it is increasingly likely that the next incremental round of sanctions will have to be watered down—as was the last round in 2008. Even if new sanctions are eventually imposed, Iran can continue to enrich uranium during the months that it will take the United States to convince Russia and China to go along.

Thus, since Iran lives in a rough neighborhood, mere incremental sanctions will be unlikely to end its quest for the ultimate deterrent against attack. The only other option would be a U.S. military attack on Iran, but this wouldn’t likely take out all of Iran’s nuclear facilities (because the U.S. doesn’t know where all of them are located) and could spur potent Iranian retaliation in Iraq, Lebanon, Gaza, and worldwide via terrorist attacks. The only way to assure an end to Iran’s nuclear program would be a full-bore invasion of that inhospitable nation, which would make the invasion and occupation of Iraq look like a picnic.

Thus, the bad news is that, even if stronger sanctions are imposed, Iran will probably get nuclear weapons eventually. The good news is that this threat is less severe than the hysteria indicates. As it did with radical and nuclear-armed Maoist China, the United States could likely deter any attack by Iran’s few warheads—provided the Iranians could eventually develop a missile with long enough range to hit the United States—through the mere presence of the massive U.S. nuclear arsenal.