US defense strategy has long been predicated on the view that military activities, maneuvers, and deployments are credible conveyers of information to both adversaries and partners about US willingness to fight in specific circumstances. Brian Blankenship and Erik Lin-Greenberg’s article, “Trivial Tripwires? Military Capabilities and Alliance Reassurance,” makes an important contribution by demonstrating that not all military activities are created equal when it comes to reassuring allies and partners. Blankenship and Lin-Greenberg rightfully capture reassurance as a product of resolve and capability—thus a “reassuring” state can provide differing acts of reassurance depending on the degree of resolve it wishes to demonstrate and the capabilities it possesses. The authors evaluate four types of reassurance, which vary according to their strength of signaling resolve and capability: (1) tripwires; (2) fighting forces; (3) transient demonstrations; and (4) offshore presences. Relying largely on surveys of defense experts in the Baltics and Central Europe, they argue that a commitment of fighting forces—such as a permanent overseas base or a large in-country ground deployment—makes countries feel safest.
The big question that comes to mind is whether these findings are valid in other theaters, such as the Indo-Pacific. The rise of China presents the greatest challenge to the security and interests of the United States and its allies since the Cold War. As China’s military capabilities have grown, so too has its aggressiveness in pushing territorial issues in the South China Sea, East China Sea, along the Sino-Indian border, and regarding Taiwan. In response, the United States has undertaken numerous military efforts designed to enhance deterrence and reassure allies, including freedom-of-navigation operations (FONOPS), a continuous presence of strategic bombers at Andersen Air Force Base in Guam, and an expanded Marine Air Ground Task Force deployed to Darwin, Australia. America’s behavior reflects an ingrained conventional wisdom: increased military presence and activities will signal US resolve, thereby will enhancing deterrence against an adversary and reassuring allies.
Whether these policy decisions in Asia will indeed contribute to a peaceful and stable Asia directly concern the central claims made in Blankenship and Lin-Greenberg’s study. In this response, Mastro argues that although their research is a step in the right direction, their conclusions do not tell us much about how the United States can reassure Asian allies and partners. Indeed, the article is one more example of the broader problematic tendency to overly rely on Europe to build understanding in the security-studies field.
Mastro makes three main points in this response. First, whether a force deployment serves as a tripwire depends on the risk to forces, not the number of forces deployed (as Blankenship and Lin-Greenberg argue). Second, how capable a country’s deployment is cannot be evaluated in isolation; the enemy’s military capabilities greatly determine the relative capabilities of different posture decisions. Third, Blankenship and Lin-Greenberg’s assumption that transient military operations are low risk (and thus signal lower resolve) is not valid in the Asian theater.