Military Coercion and US Foreign Policy reveals that despite its status as sole superpower during the post-Cold War period (1991-2018), US efforts to coerce other states failed as often as they succeeded. In the coming decades the United States will face states that are even more capable and creative, willing to challenge its interests and able to take advantage of missteps and vulnerabilities. Competition therefore will require that the United States resolve these challenges favorably without needing to resort to war. Military Coercion uses lessons derived from more than 100 coercive incidents between 1991 and 2018 to generate insight into how the US military can be used to achieve US policy goals. Specifically, it provides guidance about the ways in which, and the conditions under which, the US armed forces can work in concert with economic and diplomatic elements of US power to create effective coercive strategies.
Since the end of the Cold War the US military has been used to prosecute wars in Afghanistan and Iraq, and to destroy terrorist organizations in more than 14 countries. It also, however, has conducted regular trainings and exercises with partner nations, provided disaster relief and humanitarian aid, and supported the defense of allies through security assistance programs and overseas deployments. These and other activities are intended to prevent challenges to national interests both by putting US values into action and by demonstrating its military might.
Despite the scale and scope of the global US military presence and the extent of its military advantage, challenges to US interests do nonetheless arise. Policymakers thus also frequently use the armed forces to achieve national security objectives through shows of force and operations that occasionally include violence but still stay short of war. The movement in May 2019 of the Abraham Lincoln Carrier Strike Group to the Middle East ahead of schedule along with a bomber task force, for example, was a show of force intended to deter Iran from aggression in the Persian Gulf. The 2018 bombing of Syrian research and military facilities, similarly, was a short of war operation intended to convince Bashar al Assad to stop using chemical weapons. These and more than 100 other such actions in the post-Cold War period (1991-2018) were efforts to persuade foreign leaders not to take, or to take, specific actions that support American interests. Military Coercion and US Foreign Policy uses statistical analysis of an original dataset and expert case studies to render insight into what makes military coercion more, or less, likely to achieve US policy goals, and why. It thus narrows the gap between theory and practice, offering actionable guidance to decisionmakers seeking to achieve US foreign policy objectives without the violence and destruction caused by war. Some of its lessons affirm conventional wisdom, others are decidedly counterintuitive and stand in contrast to current US policy.
The key findings of Military Coercion are these:
- The Clarity and Specificity of Demands Affect Outcomes: Non-specific demands by the Unites States decrease the likelihood of coercive success. This may be because unclear demands increase the likelihood of misinterpretation, confusion, and therefore of inadvertent defiance; or because they suggest the US policy position is not firm but rather fluid, potentially moveable under the pressure of intentional defiance.
- Deploying Forces from Outside-in is Effective: Moving forces from outside the theater of contest into it increases significantly the likelihood of US success, very likely because putting assets and servicemembers at risk is a good indicator of resolve. This result is robust and insensitive to changes in even seemingly important contextual characteristics — for example, the extant amount of US forces permanently or typically deployed in the region. The positive effect of moving forces into the contested theater, moreover, is achieved no matter the composition of the forces deployed. This gives policymakers considerable flexibility when designing force packages for coercive operations. Notably, the use of naval and air assets increases the likelihood of success when coercing weak actors, while the deployment of ground troops makes achieving policy goals less likely. When facing strong target actors, this finding is inverted: ground troops increase the likelihood of success, air and naval deployments do not. This divergence may reflect weaker actors’ belief that in such interactions the US has inadequate resolve to suffer the loss of servicemember lives, while air and naval assets alter considerably the local balance of capabilities. For stronger actors, by contrast, the deployment of troops constitutes a trip-wire, and assets do not change appreciably calculations of the consequences of conflict – already quite high – for either party. In all cases, however, if the decision is made to deploy ground troops, they should number greater than 1,000.
- Sanctions Make Military Coercion Less Effective: Sanctions degrade significantly the likelihood of successful military coercion. This is true when sanctions are in place prior to military operations, and the negative effects are magnified by the imposition of sanctions after coercive military activity begins. It may be that sanctions suggest that the US is not willing to accept the costs of a military struggle to alter the target’s behavior, preferring to use less directly lethal instruments, thus degrading perceptions of US resolve.
- Target Characteristics can be Determinative: A lack of understanding of the target’s values and goals – of what is motivating the behavior of the decision-maker or -makers – reduces the likelihood of coercive success. Deterrence and compellence are achieved through the manipulation of anticipated costs, and it is the target’s perception of costs that matters.