Extended Deterrence and Strategic Use of Non-nuclear Military Power by Allies

• In Event: Deterrence and Coercion

Abstract

How do non-nuclear allies of the U.S. survive without nuclear weapons in the nuclear era? How do they use their conventional military power in relation to extended nuclear deterrence, and what are the determinants of their behavior? While scholarship on American nuclear strategy and extended deterrence has grown, there is much less systematic analysis of this topic despite the growing importance of strategic non-nuclear capabilities and their role in the U.S. policy of “integrated deterrence.” This paper seeks to fill the gap. It identifies three ideal types of allies’ strategies regarding their application of non-nuclear military power. The three strategies differ in their primary envisioned mechanism for managing (or even manipulating) escalation risks and increasing commitment from the United States. The paper then offers a theory on the strategic use of non-nuclear military power by U.S. allies to explain and predict allies’ behavior. The central insight underlying the argument is that the bigger the fear of de-coupling, the more risk-acceptant strategy the ally will adopt. I test this theory by comparing how two U.S. allies—South Korea and Japan—have sought to deploy their non-nuclear military capabilities for strategic effects. The findings add insight into the intricate linkages between conventional military power and nuclear weapons in extended deterrence of the post-Cold War period. They also shed light on the escalation dynamics faced by U.S.-led alliances under “integrated deterrence.”

Author

• Jung Jae Kwon, Harvard Kennedy School Belfer Center