WASHINGTON, DC – MARCH 14: First lady Michelle and U.S. President Barack Obama await the arrival of British Prime Minister David Cameron and his wife Samantha on the North Portico of the White House March 14, 2012 in Washington, DC. Cameron is on a three-day visit to the U.S. and he was expected to have talks with Obama on the situations in Afghanistan, Syria and Iran. (Photo by Chip Somodevilla/Getty Images)