Elbridge A. Colby was the lead architect of the 2018 National Defense Strategy, the most significant revision of U.S. defense strategy in a generation. Here he lays out how America's defense must change to address China's growing power and ambition. Based firmly on the realist tradition but deeply engaged in current policy, this book offers a clear framework for what America's goals in confronting China must be, how its military strategy must change, and how it must prioritize these goals over its lesser interests. The most informed and in-depth reappraisal of America's defense strategy in decades, this book outlines a rigorous but practical approach, showing how the United States can prepare to win a war with China that we cannot afford to lose-precisely in order to deter that war from happening.