President Obama with former Presidents George W. Bush, Bill Clinton, George H.W. Bush, and Jimmy Carter, at the opening of the George W. Bush Presidential Library, April 25, 2013

President Barack Obama stands with former Presidents George W. Bush, Bill Clinton, George H.W. Bush, and Jimmy Carter, at the opening of the George W. Bush Presidential Library and Museum in Dallas, Tex., April 25, 2013. Former First Ladies Laura Bush, left, and Hillary Rodham Clinton, right, are also pictured.