President Barack Obama, left, and German Chancellor Angela Merkel, right, smile during a meeting with other G7 world leaders in The Hague, Netherlands, Monday March 24, 2014, in the sidelines of the Nuclear security Summit. In a day of delicate diplomacy he sought to rally the international community Monday around efforts to isolate Russia following its incursion into Ukraine. Nuclear terrorism was the official topic as Obama and other world leaders streamed in to a convention center in The Hague for a two-day Nuclear Security Summit. But the real focus was on a hurriedly scheduled meeting of the Group of Seven industrialized economies to address the crisis in Ukraine on the sidelines of the nuclear summit. (AP Photo/Jerry Lampen, POOL)