PARIS -- President John F. Kennedy was considered a historian because of his book "Profiles in Courage," so he received periodic requests to rate the presidents, those lists that usually begin "1. Lincoln, 2. Washington ..." But after he actually became president himself, he stopped filling them out. "No one knows what it's like in this office," he said after being in the job. "Even with poor James Buchanan, you can't understand what he did and why without sitting in his place, looking at the papers that passed on his desk, knowing the people he talked with." Poor James Buchanan,...