Book excerpt: "It's striking how many of the presidents Americans venerate--Abraham Lincoln, George Washington, Franklin D. Roosevelt, and John F. Kennedy, to name a few--oversaw some of the republic's bloodiest years. Perhaps it's because they looked out for important political causes. Or maybe they just looked out for themselves. This ... book puts some of America's greatest leaders under the microscope, [positing that] their calls for war, usually remembered as brave and noble, were in fact selfish and convenient"--