President Obama Holds News Conference During Security Nuclear Summit

WASHINGTON - APRIL 13: U.S. President Barack Obama answers reporters' questions during a news conference at the conclusion of the Nuclear Security Summit at the Washington Convention Center April 13, 2010 in Washington, DC. Forty-seven countries gathered at the invitation of the U.S. government to talk about nuclear safety and how to make dangerous materials less accessible to terrorists. (Photo by Chip Somodevilla/Getty Images)