A suicide bomber in Afghanistan on Tuesday  killed Burhanuddin Rabbani, former president of Afghanistan and leader of the High Peace Council. Rabbani was in the process of negotiating an end to the war with the Taliban. The  assassination  is a devastating blow to the Afghan peace process, and the future of security in the region. Peter Galbraith, former U.N. deputy special representative for Afghanistan, and Alissa Johannsen Rubin, reporter for The New York Times, talk about what Rabbani's  assassination  could mean for the future of Afghanistan.