Proliferation and critical risk

Does proliferation increase the risk of war between new nuclear powers? Two schools of thought ‐ proliferation pessimists and optimists ‐ offer very different answers. The former stress the first‐strike danger of nuclear‐armed ballistic missiles and the resulting crisis instability as a cause of preemptive war. The latter stress the caution‐inducing effects of nuclear warheads and fear of retaliation as a check on would‐be attackers.

To bridge the gap between these two schools, Daniel Ellsberg's concept of critical risk is used to show how the likelihood of war changes as new nuclear powers enlarge and improve their missile forces. Ellsberg's framework suggests that the danger of war is low between recent proliferators but rises as nuclear stockpiles grow, thereby changing the payoffs associated with striking first or striking second and increasing the danger of war due to accidents, miscalculations, and uncontrollable interactions between rival nuclear forces.

Ellsberg's framework also suggests that the transition from weaponization to secure second strike force is likely to be long and difficult, in part because short‐range missiles like India's Prithvi are better suited to strike first than to strike second, and in part because negative control procedures reduce the value of striking second, thereby increasing the attraction of a preemptive strike.