The United States faces extraordinary challenges on both the strategic and operational levels. At the strategic level, the national security environment is in flux and many of the structures, concepts, and methods of the past no longer apply to the conditions we now face. Containment, the alliance system, our military doctrine, and many other elements of national security policy were not designed for prolonged struggle with militant Islam, an ascendant China, a Russia which is no longer a containable super power enemy but a rival for influence at America's expense, a decline in American...