The conclusion returns to the Vietnam War era, focusing on the May 4, 1970 killing of students at Kent State University by National Guardsmen and its significance for conflicting understandings of democratic citizenship, patriotism, and war. Returning also to Langston Hughes’s poem, “Let America Be America Again,” it offers concluding reflections on the relationships between land, opportunity, patriotism, and legitimate exercises of government authority. It analogizes the closing of the American frontier and emergence of a cooperative understanding of citizenship in the progressive era to the present realities of a global civilization that has exhausted the available frontiers and must find the will to engage in cooperative global problem solving.