The nuclear challenges that await the United States are increasingly about quality rather than quantity. As U.S. and Russian arsenals grew smaller and more restrained, others have moved in the opposite direction. North Korea threatens to strike Washington and Seoul. Pakistan’s posture of asymmetric escalation threatens early nuclear use if hostilities erupt in Kashmir. Russia plans to escalate to limited nuclear strikes in a conflict against NATO. Like the United States, it restricted itself in 2010 to scenarios where “the very existence of the state [was] under threat,” a testament to the humanitarian tide against nuclear war-fighting, but its reliance on tactical nuclear weapons in Eastern Europe suggests a liberal interpretation of the word “threat.” The Russian military also let blueprints slip out for a device straight out of Dr. Strangelove that could turn a major port city into a radioactive ruin. Obama should denounce such barbaric threats.