From left, First Lady Michelle Obama, former first lady Laura Bush, former first lady Hillary Clinton, former first lady Barbara Bush, former first lady Rosalynn Carter arrive for 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, First Lady Michelle Obama, former first lady Laura Bush, former first lady Hillary Clinton, former first lady Barbara Bush, former first lady Rosalynn Carter arrive for the dedication of the George W. Bush Presidential Center Thursday, April 25, 2013, in Dallas. (AP Photo/David J. Phillip)