In contrast to the Cold War bilateral global competition between the United States and the Soviet Union, the modern nuclear age features a more complex, multiplayer arena on the regional scale. With the exception of the U.S. and Russia, most major powers retain relatively small nuclear arsenals or technical hedge capabilities. The U.S., with strong interests and security partnerships in Europe, Northeast Asia, and the Middle East, must navigate through long-standing rivalries and active conflicts while attempting to divine the intentions of less experienced nuclear decision makers in charge of weak domestic institutions. As a result, analysts and policymakers must think globally about U.S. extended deterrence. How have the requirements of extended deterrence and assurance changed? Are there important threads that connect each region? What should the U.S. do differently? To explore these questions, Lawrence Livermore National Laboratory’s Center for Global Security Research, in partnership with the Carnegie Endowment for International Peace and the Pacific Forum CSIS, held a workshop on “Thinking Globally about U.S. Extended Deterrence” in Washington, DC on November 2, 2015. The workshop brought together approximately 40 U.S. and foreign deterrence specialists and government officials, all attending in their private capacities. The participants joined a day ofmore » not-for-attribution discussions on the changing deterrence and assurance requirements, the threads that connect the regions, and U.S. strategy to deal with emerging challenges. The following is a summary of key takeaways.« less