How do we prevent atrocities like those in Bosnia and Rwanda from happening again? Over the course of her career, Samantha Power - U.S. Ambassador to the U.N. and author of the Pulitzer Prize-winning book A Problem From Hell, has approached this question from diplomatic, military, and historical angles. The subject of a 12,000-word profile in this week'sNew Yorker, Power spoke recently with Anne-Marie Slaughter as part of New America's Leadership, Innovation, and Ideas series. In this excerpt from their conversation, Power and Slaughter discuss how the U.S. government, civil society, and the United Nations can innovate to pursue a peaceful and secure global future.