The U.S. has two tools when dealing with a possible nuclear Iran: threats and promises. Political scientist Alexander George would label the combination of these “coercive diplomacy.” This extremely difficult task of combing these two goes beyond a carrot and stick approach as the U.S. must not alternate between carrot and stick but use them simultaneously with credible threats and real promises. This dance is even harder to pull off given; the long history of mistrust between the U.S. and Iran, U.S.’s backing of Israel and inherent challenges of navigating Iranian decision-making.
The U.S. recent attempt’s at coercive diplomacy leaves something to be desired. A confluence of inspections, sanctions and threats led Saddam Hussein to freeze his weapons program after the Gulf War, but he refused any long-term agreement. The reasons had to do with his motives and perceptions…both of the U.S. and of Iran. Saddam was suspicious of any long-term goals of the U.S. and couldn’t appear weak to his regional rival Iran. This was made irrelevant by the threats issued by George W. Bush during the run up to the 2003 Iraq invasion. Again all threat and no credible promise.
The Iraq case may be an outlier however and it should not be assumed that coercive diplomacy doesn’t work. Former Libyan leader al-Qaddafi stopped developing weapons of mass destruction partly due to pressure and reassurances from the United States. More often than not however the U.S. has relied on overwhelming force and has missed the mark on the second pillar of coercive diplomacy…promises. Even much weaker enemies have refused to bend to the sole application of the use of force including Panama (1989), Iraq (2003), Serbia (1998), and Taliban in Afghanistan (2001). All of these failed attempts at pressure lead the U.S. to fall back on the pillar of threat and military action. Furthermore, Iran is far from alone in its defiance of U.S. pressure as North Korea has refused to give up its nuclear arsenal.
Threats can prove problematic since if they fail they force the threatening party on a path they may not want to travel. Obama’s red line on Syria’s chemical weapons back fired as soon as the weapons were used. Now, to remain credible the threat must be made good often with military force. JFK learned this lesson as well during the 1962 Cuban missile crisis. Kennedy famously joked about warheads in Cuba, “Last month I said we weren’t going to allow warheads. Last month I should have said we don’t care.” Both threats put the ball in the court of the other country. If the other party (in this case Russia or Assad) bend to the treat, they appear weak however if they cross the “red-line” whatever it may be they may or may not face consequences. Causing pain on one party and making threats can also raise the question of whether or not the party inflicting pain is serious about a deal at all.
This isn’t to say that pressure is always counterproductive. According to U.S. intelligence agencies, the Iranians temporarily stopped developing nuclear weapons in 2003 in response to the U.S. invasion of Iraq. It appears that what a U.S. diplomat said of North Korea is also true of Iran: “The North Koreans do not respond to pressure. But without pressure they do not respond.”