Since the end of the cold war, the United States has been the world's only superpower, accounting for 43 percent of the world's military expenditures. During this time, America has led major interventions into Kosovo, Afghanistan, and Iraq. Are the United States and the world better off when America follows a unilateral, interventionist foreign policy? Or should the United States reduce its overseas presence and instead emphasize international cooperation? Peter Robinson speaks with Niall Ferguson and Ivan Eland.