President Obama gestures during a joint news conference with British Prime Minister David Cameron on Monday, May 13, 2013, in the East Room of the White House in Washington, where they talked about subjects ranging from Syria's civil war to preparations for a coming summit in Northern Ireland. (AP Photo/J. Scott Applewhite)
President Barack Obama gestures during a joint news conference with British Prime Minister David Cameron, Monday, May 13, 2013, in the East Room of the White House in Washington, where they talked about subjects ranging from Syria's civil war to preparations for a coming summit in Northern Ireland. (AP Photo/J. Scott Applewhite)
President Barack Obama gestures during a joint news conference with British Prime Minister David Cameron, Monday, May 13, 2013, in the East Room of the White House in Washington, where they talked about subjects ranging from Syria's civil war to preparations for a coming summit in Northern Ireland. (AP Photo/J. Scott Applewhite)
President Obama gestures during a joint news conference with British Prime Minister David Cameron on Monday, May 13, 2013, in the East Room of the White House in Washington, where they talked about subjects ranging from Syria's civil war to preparations for a coming summit in Northern Ireland. (AP Photo/J. Scott Applewhite)
President George W. Bush and Prime Minister Tony Blair of Great Britain walk on the grounds of Hillsborough Castle Monday, April 7, 2003, in Hillsborough, Northern Ireland. Photographs by Eric Draper from Front Row Seat: A Photographic Portrait of the Presidency of George W. Bush(Copyright © 2013). For more information visit www.utexaspress.com
**FILE** Exiled Tibetan spiritual leader the Dalai Lama greets people after walking over the Londonderry Peace Bridge, during a visit to Londonderry, Northern Ireland, on April 18, 2013. The Dalai Lama walked across the city's iconic Peace Bridge with hundreds of children from across the religious divide. (Associated Press)
**FILE** Exiled Tibetan spiritual leader the Dalai Lama greets people after walking over the Londonderry Peace Bridge, during a visit to Londonderry, Northern Ireland, on April 18, 2013. The Dalai Lama walked across the city's iconic Peace Bridge with hundreds of children from across the religious divide. (Associated Press)
** FILE ** Britain's Queen Elizabeth II arrives for a Service of Thanksgiving in St. Macartin's Cathedral in Enniskillen, Northern Ireland, on Tuesday, June 26, 2012, as part of the celebration of her 60 years on the throne. (AP Photo/Peter Morrison)
Spectators watch Rory McIlroy, of Northern Ireland, tee shot on the seventh hole during a practice round for the Masters golf tournament Tuesday, April 9, 2013, in Augusta, Ga. (AP Photo/David Goldman)
