The sources of threat credibility in extended deterrence

For deterrence to work, a potential attacker needs to perceive the deterrer's threats as capable and credible for retaliation. The issue of relative capabilities has been extensively analyzed, yet the core problem concerns credible intentions. The strategic literature is largely influenced by commitment theory prescribing various "manipulation of risk" strategies intended to enhance threat credibility. A few analysts, however, challenge this view and recognize the importance of "intrinsic interests" in the issues at stake (i.e., inherent credibility), which can limit the effectiveness of costly signals. These two alternative views are quantitatively tested in the cases of major-powers deterrence from 1895 to 1985. A new measure of the observable category of inherent credibility is also introduced, consisting of the regional interests of major powers in the area of dispute. The results indicate strong and significant effects of regional interests on both the onset and outcomes of extended-immediate deterrence, thus suggesting relevant theoretical and policy implications.