Guerra, paz e armas nucleares

How do states act after they get nuclear weapons?, por James Fearon (The Monkey Cage):

All this talk about a possible US and/or Israeli preventive war against Iran got me wondering about the historical record concerning the conflict behavior of states after they acquired nuclear weapons. Does the rate at which states are involved in serious international disputes tend to go up, down, or see no change after they get the bomb?

Advocates of preventive war on Iran like Matthew Kroenig expect Iran to become much more aggressive if it gets nukes. “Proliferation optimists” like Ken Waltz, by contrast, argue that we have repeatedly expected terrible things from nuclear-armed adversaries but repeatedly found, if anything, the opposite to be the case. For example, both the Soviets and the US contemplated preventive strikes to prevent Mao from getting the bomb, as they considered him, not without some evidence, to be aggressive, dangerous, and fanatical. But the Chinese bomb was arguably followed by a more status quo oriented Chinese foreign policy. (...)

So I put it together myself, using Zeev Maoz’s version of the Correlates of War’s militarized interstate dispute data. The following graph shows, for each of the nine states that acquired nuclear capability at some time between 1945 and 2001, their yearly rate of militarized disputes in years when they didn’t have nukes, and the rate for years when they did. Note that for the US we have no data on dispute rate without nukes in this period since we got them in 1945; the rate for non-nuclear years for Russia/USSR is only for 1945-1948; the rate for South Africa (SAF) is for 1982-90; and the dispute data only goes to 2001.

China, France, India, Israel, Pakistan, and the UK all saw declines in their total militarized dispute involvement in the years after they got nuclear weapons. A number of these are big declines. USSR/Russia and South Africa have higher rates in their nuclear versus non-nuclear periods, though it should be kept in mind that for the USSR we only have four years in the sample with no nukes, just as the Cold War is starting.