Like the Arab-Israeli Six-Day War of 1967, the U.S. invasion of Iraq is fundamentally reordering regional politics and security in ways that will be felt for a generation, if not longer.1 The Pandora's Box opened by the United States in Iraq adds a new level of unwelcome complexity to an already strained regional fabric. Threats to regional security stem from global, interstate, and intrastate sources. The complicated, multidimensional, and interrelated natures of these threats suggest that the United States must reassess strategy and policy if it is to protect and further its regional interests. The objective of this monograph is threefold: (1) deconstruct the threats to regional security and stability in the aftermath of the Iraq invasion; (2) determine whether U.S. strategy is tailored to the threat environment; and (3) suggest steps that can be taken to bring strategy and the environment into closer alignment. Such a process runs counter to the current defense planning methodology paradigm used by the Defense Department. Both the 2006 Quadrennial Defense Review and its predecessor released just after the September 11, 2001 (9/11) attacks called for the divorce of U.S. strategy and defense planning from specific regional threats and contingencies. Instead, the planning documents called for the development of "capabilities portfolios" to enable U.S. military forces to fight in a series of different operational environments: irregular warfare against nonstate actors, traditional interstate warfare, catastrophic attacks using weapons of mass destruction, and disruptive attacks from adversaries using cyber-warfare or other advanced technologies. This monograph argues that the United States needs to reconnect its strategy, policy, and defense planning to regional environments if it is to have any hope of mitigating threats to its interests, not just in the Middle East, but around the world. The altered distribution of power has changed the nature of the security dilemma for regional states-the critical structural dynamic in interstate interactions and the engine driving the region's geopolitical instability. The security dilemma refers to a term of art from the international relations theory of realism, which argues that states are primarily motivated by self interest and exist in an anarchical, self-help system. The modern form of realism, the so-called "neo-realist" paradigm developed by Kenneth Waltz, holds that actions taken by states to protect and enhance their security create in turn insecurity for surrounding states that causes states to balance and counterbalance each other in a never-ending cycle.2 Under this theory, the security dilemma of states and the relative distribution of power in the international system are a structural dynamic that governs interstate interactions. States pursue security through a combination of arms buildups and political-military relationships with other strong states in alliances. Pursuit of nuclear weapons-the putative ultimate guarantor of state security-and/or nuclear partners is explained under realist theory as a logical result of states' quest for security. That quest for security is operationalized by states' political leadership using a rational decisionmaking process that apportions available resources to meet the security needs of the state.