Former President George H.W. Bush and former president George W. Bush and his wife Laura Bush laugh while former president William J. Clinton speaks during the dedication of the George W. Bush Presidential Center Thursday, April 25, 2013, in Dallas. (AP Photo/David J. Phillip)

Photo by: David J. Phillip

Former President George H.W. Bush and former president George W. Bush and his wife Laura Bush laugh while former president William J. Clinton speaks during the dedication of the George W. Bush Presidential Center Thursday, April 25, 2013, in Dallas. (AP Photo/David J. Phillip)