We operate in a complex and dynamic security environment. Planning assumptions that held for decades are no longer relevant; assumptions that are relevant today may not be next year. Asymmetric threats are exploding, and the level of complexity and the challenges that we face will only continue to grow. The United States simply cannot meet every challenge unilaterally. Resources are only part of the problem. Even if we had unlimited resources, we would still need the perspectives and skills that our partners can bring to bear to address increasingly complex issues. Deep, enduring partnerships based on shared values, mutual benefit, and trust are vital to maintain our security. Our partners bring critical capabilities that we often cannot duplicate. They also bring a multilateral approach to security that is increasingly important for economic, cultural, and political reasons. While the United States will maintain its role as the preeminent global power...