An engraving of the assassination of President Abraham Lincoln at Ford's Theatre in Washington on April 14, 1865. Lincoln died the next day. De Agostini Picture Library/De Agostini/Getty Images hide caption

itoggle caption De Agostini Picture Library/De Agostini/Getty Images

President Obama with Israeli Prime Minister Benjamin Netanyahu at the White House in 2013. The two have never had a warm and fuzzy relationship. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

Josef Joffe, author of The Myth of America's Decline, says the U.S. remains a world leader in education, economic performance and innovation. Samuel LaHoz/Intelligence Squared U.S. hide caption

itoggle caption Samuel LaHoz/Intelligence Squared U.S.