Security scholars have long recognized that compellence/coercion is more difficult to achieve than deterrence. (Although both deterrence and compellence require coercion, coercion is commonly used interchangeably with compellence. I will do so here.)
There are two, interrelated reasons for this. First, “deterrence aims to persuade the opponent not to initiate action” while “compellence aims to persuade the opponent to change his behavior.” In most cases in international politics, this means that deterrence demands that an adversary not acquire or attempt to acquire something new (more territory, a nuclear weapon), whereas coercion demands that the target state give up something it already possess (part of its territory, a uranium enrichment capability). Nations, like individuals, value what they already possess more than what they only aspire to. As a result, they are much more likely to be deterred than coerced.
Secondly, because of the different types of demands being made, coercion usually places the impetus for initial action on the coercer, whereas deterrence places the burden of first action on the target state. For example, to deter the Soviet Union from overrunning Western Europe, the U.S. only needed to threaten massive retaliation if the Red Army crossed the Fulda Gap. Unless the Red Army came storming into Western Europe, the U.S. wasn’t required to take any actual action against the Soviet Union.Enjoying this article? Click here to subscribe for full access. Just $5 a month.
By contrast, because coercion is demanding a state give up something, usually the coercer must take the initiative. This usually entails imposing some sort of discomfort on the target state backed by threats to increase this level of discomfort if its demands are not met. In addition, the coercer promises to end the pain it is imposing on the target state once its demands are met. For instance, in order to convince Iran to stop enriching uranium to 20 percent, the U.S. and its allies have imposed increasingly harsh sanctions on Tehran and threatened possible military action in the future. Conversely, it has promised Iran that the sanctions will be lifted and military action won’t be taken if it accedes to Western demands.
For these reasons, it shouldn’t come as a surprise that coercion often fails, regardless of the kind of pressure applied to the target. Indeed, the three most common tools of coercion in modern times — naval blockades, strategic bombings, and economic sanctions — all have fairly abysmal success rates.
Although not as common in recent years, history has seen many instances of nations imposing blockades against their adversaries. They have rarely worked on their own, especially when the target state is a great power. John Mearsheimer, for instance, notes that there have been eight instances of great powers establishing naval blockades against other great powers. In his estimation, in none of these cases did these blockades prove decisive by themselves.
Strategic bombings have replaced naval blockades as modern statesmen’s go-to form of military coercion. Still, they haven’t proven all that more successful at securing concessions than naval blockades. Mearsheimer’s writings are again instructive. He notes that there have been five instances in which great powers initiated strategic bombing campaigns against other great powers. According to his analysis, three of these failed unambiguously while in two cases — Italy and Japan — they played a complementary if secondary role in securing the political concessions sought.
Mearsheimer, who is writing in 2001, also finds there are nine examples of great powers carrying out strategic bombing campaigns against non-great powers, usually in combination with other forms of kinetic action. In five of these nine cases the coercer was unsuccessful entirely. While the coercer was ultimately successful in the remaining four cases, strategic bombing played only a marginal role in this success in all but one of the cases, at least according to Mearsheimer. Strategic bombing campaigns haven’t proven much more successful since 2001 either, as operations in Afghanistan, Iraq, and Libya all required significant ground forces to succeed.
Finally, the most popular tool for coercion today is economic sanctions. Even sanctions’ strongest proponents only claim they have a modest track record. For example, one of the more optimistic studies on sanctions found they at least partially worked in 40 of 115 cases, or 34 percent of the time. Moreover, they admitted that the partially successful cases were heavily drawn from examples of minor disputes in which the concessions being demanded were limited in scope. Even still, some scholars dispute the results of this study, contending it grossly overstates the effectiveness of sanctions. Robert Pape, for instance, reviews the data and finds that only 5 of the 40 so-called successes stand up to scrutiny. If his analysis is correct, sanctions only worked in 4 percent of the cases in which they were tried.
Despite its shoddy track record, leaders continue to be attracted to coercion’s lure of achieving important foreign policy objectives on the cheap. In fact, in the unipolar era, coercion has far eclipsed deterrence as the United States’ primary means for achieving important goals abroad. Other countries like Russia also pursue overt and covert coercion to achieve their objectives. Thus, states continue to search for methods for making coercion more successful.
In his path-breaking study on the subject, Pape argues that coercion works when the target state determines that “the costs of resistance and the probability of suffering these costs” exceed the costs of making the concessions and the probability of avoiding these costs through continued resistance. In other words, coercers have three ways to affect target states’ calculus on whether to concede or not: make the punishment more unbearable (increase the costs of resistance), make resistance more futile (decrease the probability conceding can be avoided), and/or make the costs of conceding less unpalatable.
Most states have spent the bulk of their energies on finding ways to make the punishment more unbearable. For the U.S. in recent years, the Treasury Department has led the way by finding methods to make sanctions more effective. By threatening to cut off access to U.S. financial markets, America has convinced most banks to avoid dealing with Iran and North Korea whether such deals would be in violation of sanctions or not. Pape himself argues that coercion efforts should be aimed at reducing the target state’s ability to resist. For example, if the coercer destroys much of the armed forces in a territory it wishes to accumulate, the target state may agree to the coercer’s demands more readily.
It strikes me that more effort should go in to the third method; namely, reducing the demands being made on the target state to make it more palatable to accept them. As noted above, economic sanctions are believed to have been relatively effective in cases where the concessions demanded were not exorbitant. Of course, in some cases the concessions needed cannot be negotiable. These are the exceptions to the rule, however. Moreover, states can handle these cases better by having the foresight to initially demand more than the bare minimum of what they can accept.
A couple of recent cases have highlighted how reducing demands can help achieve important foreign policy objectives. For example, in dealing with the Syria crisis, initially the U.S. demanded that Bashar al-Assad relinquish power, which was essentially a non-starter for at least Assad himself. Following the chemical weapons attack over the summer, the U.S. reduced its demands to Assad merely giving up his chemical weapons stockpile. Rather than come under attack, Assad assented to this demand.
Similarly, while the U.S. has long demanded that Iran halt all domestic enrichment, in reality it can accept some enrichment on Iranian soil so long as it is under international safeguards. Despite the effectiveness of the current sanctions regime, Iran will never accept a complete halt to its enrichment program. It will sign a deal that limits its enrichment program, something the U.S. can also live with.
Thus, while designing more effective modes of punishment can certainly help make coercion successful, ultimately reducing demands may be necessary. That’s because at some point there are limits to what one can achieve without the complete destruction of the other side’s forces.