Extended Deterrence and Assurance in Multiple Domains

Abstract

Cross-domain deterrence must contend not only with the technological complexity of modern military power but also with the political complexity of alliance relationships. The proliferation of domains might affect commitments to allies. This chapter draws on the precedent of the U.S. nuclear triad and the underappreciated relationship between platform diversity and the credibility of commitments. As it turns out, the advent of intercontinental and submarine-launched ballistic missiles inadvertently undermined U.S. deterrence commitments in East Asia and Western Europe. This chapter argues that the plethora of capabilities emerging in the twenty-first century will enable allies and adversaries alike to engage in risky behavior while undermining the United States’ willingness to intervene overseas. The chapter concludes with implications for U.S. polity and that of its alliance partners, as well as predictions about the general evolution of extended deterrence strategies in an increasingly cross-domain system.