Center for Strategic and Budgetary Assessments' (CSBA) Senior Fellow Dr. Evan Montgomery’s Extended Deterrence in the Second Nuclear Age: Geopolitics, Proliferation, and the Future of U.S. Security Commitments report provides an overview of U.S. extended nuclear deterrence commitments and how Washington plans to uphold them; describes the main challenges to extended nuclear deterrence in Europe, East Asia, and the Middle East; and sketches out what updated extended nuclear deterrence postures might look like across all three regions in light of these challenges.