Is alliance credibility interdependent?

Abstract

How might changes in the credibility of one alliance relate to the credibility of other alliance commitments? Debate between competing views on this question spans decades in part because systematic tests are difficult. We contribute systematic evidence with a new measure of credibility in U.S. alliances and novel technique to estimate interdependence. Our measure draws on expert ratings of allied beliefs over U.S. credibility and our analysis employs Gaussian process regression to analyze credibility. We find strong correlations in allied credibility perceptions within regions and little correlation across regions. Supplementary analyses suggest that these correlations reflect common unobservables and a small impact of shared perception of past U.S. behavior.