Richard and Liz Cheney sign copies of their book at the Reagan Library (9 images)

Former vice president Richard Cheney and his daughter Liz Cheney sign copies of their book "Exceptional: Why the World Needs a Powerful.America" at the Ronald Reagan Presidential Library in Simi Valley, California on September 9, 2015. Mr. Cheney cited what he called the foreign policy failings of the Obama administration, denouncing what he called a "shameful deal" with Iran that would risk a new Holocaust and possibly lead to a nuclear attack on the United States. "It is madness," he said. Photo by Jim Ruymen/UPI

Former vice president Richard Cheney and his daughter Liz Cheney discuss the book they co-wrote, "Exceptional: Why the World Needs a Powerful America" following a book signing at the Ronald Reagan Presidential Library in Simi Valley, California on September 9, 2015. Mr. Cheney cited what he called the foreign policy failures of the Obama administration, denouncing what he called a "shameful deal" with Iran that would risk a new Holocaust and possibly lead to a nuclear attack on the United States. "It is madness," he said. Photo by Jim Ruymen/UPI

Former vice president Richard Cheney and his daughter Liz Cheney's book they co-wrote, "Exceptional: Why the World Needs a Powerful America" on display at the Ronald Reagan Presidential Library in Simi Valley, California on September 9, 2015. Mr. Cheney cited what he called the foreign policy failures of the Obama administration, denouncing what he called a "shameful deal" with Iran that would risk a new Holocaust and possibly lead to a nuclear attack on the United States. "It is madness," he said. Photo by Jim Ruymen/UPI

Former vice president Richard Cheney and his daughter Liz Cheney sign copies of their book "Exceptional: Why the World Needs a Powerful.America" at the Ronald Reagan Presidential Library in Simi Valley, California on September 9, 2015. Mr. Cheney cited what he called the foreign policy failings of the Obama administration, denouncing what he called a "shameful deal" with Iran that would risk a new Holocaust and possibly lead to a nuclear attack on the United States. "It is madness," he said. Photo by Jim Ruymen/UPI