This month, the U.S. expanded its already aggressive sanctions on Iran by penalizing several companies suspected of aiding the country's nuclear program or helping the regime evade trade restrictions. The U.S. Senate also introduced legislation that could prevent Iran from accessing more than $100 billion held in overseas banks.
The goal of these actions is to get Iran's ruling clerics to give up their pursuit of a nuclear weapon. Although harsher economic sanctions will undoubtedly ramp up the costs imposed on Iran, they won't necessarily translate into desired political outcomes. Research indicates that many variables play a role in the success or failure of sanctions. Most important, for sanctions to achieve their goals they must be paired with a clear and comprehensive diplomatic road map - one that's lacking in Iran.
Strategies that focus solely on economic sanctions usually fail, for several reasons. Although states that are politically fragile and economically weak may sometimes be easier to coerce through sanctions, they also may present unique challenges.
Tufts University professor Daniel Drezner has described a "sanctions paradox" that is particularly salient with Iran. He argues that states targeted with sanctions are often primed for failure because they already have higher expectations for future conflict and are therefore more concerned about material and reputational losses. As a result, "the target will be concerned about any concessions in the present undercutting its bargaining position in future interactions." Colonel Phil Haun, a professor at the U.S. Naval War College, has examined why weaker states may be resistant to complying with demands from stronger ones despite increasing costs. One reason is that concessions may threaten the survival of the regime or the state itself.
Other research indicates that sanctions are less likely to be effective against autocracies, such as Iran, than against democracies. Under a dictatorship, there's a more tenuous link between the population, which feels the costs of sanctions most directly, and the regime that has the ability to modify the state's behavior.
Are there ways to ameliorate these challenges? In my research, I looked at more than 100 episodes in which the U.S. imposed sanctions on other countries. I found that diplomatic engagement makes sanctions more effective, whereas disengagement has the reverse effect. When the U.S. closes its embassy in a targeted country, for instance, the probability that sanctions will fail increases to 73 percent from 42 percent.
That's because engagement produces better intelligence on the targeted country and enhances communication channels. It improves the ability to convey demands, target the correct entities, monitor the impact of sanctions on the ground and calibrate policies over time. Diplomacy also provides a window into the regime's decision-making processes, motives and vulnerabilities. The Treasury Department's Office of Foreign Assets Control, for example, relies heavily on intelligence from within a country to assist in making sanctions policies.
Increased diplomatic interaction also helps clarify the nature of the demands on a sanctioned country and resolve ambiguity. A 2011 study of almost 900 sanctions episodes over three decades found that specific demands had a success rate of 53 percent, whereas only 18 percent of ambiguous demands were met. These findings suggest that strong parallel diplomatic efforts have the ability to directly strengthen punitive economic measures.
Libya offers a compelling example. From 1980 to 1989, U.S. policy toward Libya was predicated on diplomatic isolation while economic sanctions were being imposed. During this period, there was a significant reduction in communication between the U.S. and Libyan officials, and there was a decline in intelligence gathering. Minimal progress was made in cracking down on terrorism or in trying to undermine or remove Moammar Gadhafi, Libya's dictator at the time. When diplomatic engagement was renewed from 1999 to 2006, sanctions were much more successful. Libya acknowledged responsibility for the 1988 Lockerbie airliner bombing and paid compensation to victims' families. It also agreed to give up its weapons of mass destruction and admit international inspectors.
In Iran, imposing higher financial costs for the regime's failure to halt nuclear armament is necessary, but not sufficient. Although talks have thus far been marked by delays and disagreement, the U.S. and the five other powers negotiating with Iran must still be willing to sustain diplomatic engagement, unambiguously articulate their demands, and set forth a road map for compliance and the eventual removal of sanctions.
There is no shortage of ideas for increasing such engagement. A plan to re-establish full diplomatic relations between the U.S. and Iran over time, starting with direct talks between high-level officials, would be a good first step. Flynt Leverett and Hillary Mann Leverett have proposed a deal to extend security assurances to Iran, lift sanctions and acknowledge the regime's place in the international order in exchange for Iran ending its pursuit of nuclear weapons, support for terrorism and opposition to an Arab-Israeli agreement. Other scholars have suggested establishing an international group that would enrich uranium for peaceful purposes inside Iran, with greater supervision.
Breaking through the barriers to engagement is never easy and often politically unpopular. But it is possible. Even during the Cold War, President Ronald Reagan was willing to engage directly with the Soviet Union. The U.S. should focus on trying to come up with new and creative diplomatic efforts that give it greater insights into the Iranian regime's decision-making. Doing so might create openings that transform the dynamics of the relationship.
Tara Maller is a research fellow in the National Security Studies Program at the New America Foundation.