It should be a very short list. From Doug Bandow at theamericanconservative.com:
America’s continued post-Cold War commitment to extended deterrence risks losing U.S. cities to other nations’ fights.
Most Americans are horrified by the prospect of nuclear war. Yet during his recent summits with the leaders of South Korea and Japan, President Joe Biden reaffirmed Washington’s willingness to use nuclear weapons to defend both nations. Even though the U.S. risks nuclear attack in return.
“Total” conventional war is horrific. Nuclear weapons greatly magnify the threat. The U.S. and Russia could destroy each other and the rest of the planet. The realization of how close Washington and Moscow came to nuclear war during the Cuban Missile Crisis fuels present efforts to eliminate nuclear weapons. However, mankind has opened Pandora’s Box and the deadly knowledge is out.
The principal defense against nuclear weapons, given the difficulty in preventing their use, is deterrence. Attack me and I will destroy you in return. This mutually assured destruction is unsatisfactory, since the failure of deterrence leaves both sides devastated and dead. Horror at this possibility led Ronald Reagan to advance the Strategic Defense Initiative. Alas, the likelihood of thwarting a determined attack by even a medium-size nuclear power is slight, at least in the near term.