WASHINGTON, DC – MARCH 14: U.S. President Barack Obama (R) and British Prime Minister David Cameron review the U.S. Army’s Old Guard Fife and Drum Corps during an official arrival ceremony on the South Lawn of the White House March 14, 2012 in Washington, DC. Cameron is on a three-day visit to the U.S. and he is expected to have talks with Obama on the situations in Afghanistan, Syria and Iran. (Photo by Alex Wong/Getty Images)