Why does the United States have a Marine Corps? Years ago, Lieutenant General Victor Krulak provided the sentiment-laden answer, “because the United States wants a Marine Corps.”1 His response reflects the long-standing confidence of the American people in the Marines. To the public, when trouble arises, the phrase “Send in the Marines” connotes both a demand for action and a presumption of success. It implies an expectation of discipline, prompt response, and creativity that brings dread to our nation’s adversaries, trust to our friends and allies, and hope to those in need. In recent years this intuitive understanding has been reinforced by the contributions of Marines toward alleviating human suffering following natural disasters in Haiti and Pakistan, toppling the regime in Iraq, eradicating the endemic violence that ensued within al Anbar Province, and building partners in Afghanistan.