When President Obama takes the podium on Sept. 28 during the United Nations General Assembly, he will be part of a cavalcade of world leaders - from Russia to Iran - whose nations are at the fore of global crisis and conflicts.
NBC News: UN General Assembly – What to watch for as global powers meet
UN Secretary General Ban Ki-moon (R) shakes hands with US President Barack Obama after his speech on the Post-2015 Development Agenda at the United Nations on Sept. 27, 2015 in New York.