According to the United Nations, last year some eight million people around the world were displaced from their homes by conflict and social upheaval””the largest number ever recorded in a single year. This coming week (May 23-24), as the UN convenes the first World Humanitarian Summit, correspondent Kim Lawton talks with prominent Roman Catholic theologian and ethicist Rev. David Hollenbach SJ about the global refugee crisis and the moral obligations he believes the US government and individual Americans have to respond.