In 2009, presidents Barack Obama and Dmitry Medvedev pledged to sign a bilateral treaty to limit the nuclear arsenals of the United States and Russia to approximately 1,500 deployed nuclear weapons and 750 delivery systems. While this represents a significant reduction from cold war–era levels, the two countries still retain more than 90 percent of the world"s nuclear weapons. As good-faith progress toward President Obama"s stated commitment "to seek the peace and security of a world without nuclear weapons," both countries need to begin negotiating a follow-up bilateral treaty to reduce their respective arsenals. Micah Zenko offers specific recommendations for U.S. policy on four strategic and technical issues that such a treaty would raise:• Beginning high-level discussions with U.S. allies on the tradeoffs between extended deterrence and deeper nuclear cuts• Promoting the joint U.S.-Russia development of missile defense radar and interceptors• Proposing transparency and confidence-building measures for deployed U.S. and Russian tactical nuclear weapons• Developing a framework to account for deploying advanced conventional weapons on nuclear-capable delivery systems.At a time of global nuclear uncertainty, this report defines a path to greater security and commitment to a nonnuclear world.