Are nuclear weapons obsolete? Nuclear policy lessons from Russia's invasion of Ukraine.*

The role that nuclear weapons played in shaping the conflict in Ukraine raise important questions about nuclear deterrence, proliferation, and disarmament. The evidence suggests that the utility of nuclear weapons as military and political tools is extremely limited. From the military point of view, this conflict showed that there are no military missions that nuclear weapons can accomplish on the battlefield. Even though nuclear weapons can be used to attack civilian targets in an attempt to change the strategic outcome of the war, the political cost of such an attack would be unacceptably high. The international community has unequivocally condemned nuclear threats, making nuclear use all but impossible. While it is true that Russia's nuclear status played the key role in enabling the aggression and in deterring the West from directly intervening in the war, it proved ineffective in preventing the West from providing military and other forms of assistance to Ukraine. As for the enabling role of nuclear weapons, it is clear that after the war Russia will be in a much weaker economic, political, and security position than it was in before the conflict began. Indeed, nuclear weapons proved to be detrimental to Russia's national security. This war also has a strong nuclear proliferation aspect to it. It is often argued that Ukraine would have prevented the conflict had it possessed nuclear weapons. However, even if nuclear weapons may have deterred the invasion, it is highly uncertain whether they could have prevented the annexation of Crimea. Finally, nuclear weapons are often credited with providing security to NATO states. The war in Ukraine demonstrated that this is not the case. While NATO may have protected itself from an invasion, it has not isolated itself from the war and bears an enormous risk of a catastrophic escalation that it cannot fully control. The war in Ukraine shows that nuclear weapons cannot be relied on to provide security and stability. This talk is co-sponsored by the University of Illinois Physics Department.