From left, President George H.W. Bush, former president George W. Bush and Laura Bush listen to former president William J. Clinton 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

From left, President George H.W. Bush, former president George W. Bush and Laura Bush listen to former president William J. Clinton during the dedication of the George W. Bush Presidential Center Thursday, April 25, 2013, in Dallas. (AP Photo/David J. Phillip)