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...