On GPS Sunday, Fareed sits down with two former U.S. Treasury Secretaries - Larry Summers on the left and Hank Paulson from the right. What's the one glaring troublespot in the U.S. economy? And is the nation losing out to China? Then, a pope and a politician duke it out over ancient history. Fareed explains what harsh words from Turkey tell us about that country today. And, as Earth Day approaches, Jeffrey Sachs tells Fareed why 2015 is our LAST chance to act on climate change.