Former British defense minister Denis Healey once observed that "it takes only five percent credibility of American retaliation to deter the Russians but ninety-five percent credibility to reassure the Europeans." He was referring to the Cold War–era difficulty of convincing NATO allies of the credibility of U.S. extended-deterrence commitments, but his words continue to ring true. An abundance of new challenges accompany extended deterrence, assurance, and reassurance in the second nuclear age, as the United States continues to guarantee the sovereignty of more than 30 countries worldwide. Nowhere are these challenges more pronounced than in Northeast Asia, where assuring allies of the United States' willingness and ability to defend them must be an integral part of U.S. foreign policy. Given that the U.S.-China relationship will be the most important geopolitical dynamic of the next several decades, what are the tasks of and challenges to U.S. extended deterrence in the Pacific?
This chapter begins by defining key terms, including extended deterrence, assurance, and reassurance. It then briefly reviews the requirements of and challenges to extended deterrence during the Cold War before moving on to demonstrate why extended deterrence in the Pacific during the second nuclear age is a unique task. After summarizing current nuclear policy, we identify and analyze five specific challenges to extended deterrence in the Pacific. The chapter then analyzes the implications of these challenges for U.S. nuclear force structure, as well as for nuclear declaratory policy and allied consultation efforts. On the basis of these implications, we offer a number of policy recommendations on how the United States should approach its extended deterrence, assurance, and reassurance efforts in this crucial region over the coming decades.