What security benefits do nuclear weapons provide to their possessors? After accounting for two potential selection effects, the empirical evidence from all international crises from 1945 to 2000 indicates that opponents of nuclear-weapon states demonstrate restraint in turning to violent aggression. Nuclear weapons, however, have little effect on overall crisis occurrence. The authors also explore the behavioral effects of nuclear-weapons programs and find that program states have a higher proclivity for crisis occurrence.
Beardsley, Kyle, and Victor Asal. 2009. "Nuclear Weapons as Shields." Conflict Management and Peace Science 26 (July): 235-255. https://journals.sagepub.com/doi/abs/10.1177/0738894209104550