Nuclear arms control has had a very rough few years. The latest piece of bad news comes from Russia. Earlier this week, Vladimir Putin announced that Russia is “suspending its membership” in New START, a treaty that limits the number of deployed nuclear warheads and launchers for Russia and the United States. While New START is not completely dead yet, Putin’s announcement is the latest in a series of unfortunate events for the arms control regime. What is New START? Arms control negotiations and treaties have helped restrain nuclear competition between the United States and Russia, the...