Capability, Credibility, and Extended General Deterrence

Deterrence theory suggests that extended general deterrent threats are likely to be more effective when a potential challenger views them as capable and credible. When states sign formal defense pacts, they are making explicit extended general deterrent threats. Thus, the population of defense pacts allows us an opportunity to judge the efficacy of extended deterrent threats with different characteristics. We find that defense pacts with more capability and more credibility reduce the probability that a member state will be a target of a militarized dispute. We also find that states can affect the capability and credibility of their extended deterrent threats through alliance design. Members of defense pacts that include higher levels of peacetime military coordination are less likely to be attacked. This analysis provides support for deterrence theory in the context of extended general deterrence. It also provides evidence that should aid policymakers in designing security structures to meet their goals.