Stepping Out From Under the Umbrella: Alliance Credibility and Nuclear Proliferation

Abstract

What are the causes and consequences of alliance credibility in international politics? While the credibility and reputation literature has examined whether or not credibility matters in international politics, these studies fail to differentiate between a state’s reputation vis-à-vis adversaries and a state’s reputation vis-à-vis allies. This project develops a mechanism for alliance credibility by observing the relations between the great power ally’s crisis behavior and the weaker ally’s nuclear behavior post-crisis. I theorize that the critical determinant of the non-nuclear allies’ decision to develop their own nuclear weapons is the patron ally’s lack of credibility, a function of the patron ally’s interest and resolve. Salient crises provide opportunities for allies to observe and assess credibility because they provide two important sources: private information and credible commitment. When patron allies fail to demonstrate credibility—either by failing to support a non-nuclear ally in a crisis (conflict of interest), or conceding defeat in a crisis (lack of resolve)—non-nuclear allies will pursue an indigenous nuclear weapons program.

This study develops and tests this theory using multi-methods research: statistical analysis using dataset of ally’s crisis behavior and nuclear proliferation and process-tracing methods in historical case studies of nuclear proliferation within military alliances. The three cases are comprised of the Chinese nuclear program after the Sino-India Border Crisis in 1959, the South Korean nuclear program in 1970-75 after series of salient crises on the Korean peninsula and Vietnam, and the Taiwanese nuclear weapons program in the late 1960s after the Third Taiwan Strait Crisis. The conclusion presents a new theory of nuclear proliferation within military alliances and provides policy recommendations for alliance management and nuclear non-proliferation.