Grand strategy is an often controversial term in the vocabulary of United States foreign policy. Competing visions of the U.S. role in global affairs lead to watered-down policy pronouncements which must be evaluated in hindsight by their manner of implementation for a clear interpretation. In his latest book, Restraint: A New Foundation for U.S. Grand Strategy , Massachusetts Institute of Technology professor Barry Posen makes such an assessment. He identifies a relatively consistent pattern of activist behavior which he dubs a grand strategy of “Liberal Hegemony.” This strategy, he argues, has been wasteful and counterproductive in securing U.S. national security interests, and he offers a competing vision for U.S. national security strategy. While most readers will find his arguments against Liberal Hegemony compelling, his grand strategy of “Restraint” will be divisive on a number of levels. Posen is clear and systematic throughout the book in defining his terms and developing his arguments. He scopes his use of the term grand strategy along national security lines related to the generation of military power, avoiding potential pitfalls of debate over issues such as public health or domestic policy. He defines Liberal Hegemony as a strategy of securing the superpower position of the United States largely through the active promotion of democracy, free markets, and Western values worldwide. Variations of this strategy have been championed on both sides of the political aisle by liberals and neoconservatives. His counterproposal, Restraint, is a realist-based grand strategy which focuses U.S. military power on a narrow set of objectives, relies on “command of the commons” to ensure global access, avoids entanglement in foreign conflicts, and actively encourages allies to look to their own defense. Posen advances a largely maritime-focused strategy to command the world’s commons.