The nation turns to it as an emotional, political, and patriotic symbol in good times and bad. Americans fly it everywhere we live and everywhere we go, from front porches in Florida to pickup trucks in Alaska. We display the red-white-and-blue American flag at festive events to celebrate and, at times of national tragedy, to grieve and show our resolve. We wrap ourselves in it in displays of patriotism, politics, nationalism, and jingoism.The thirteen-stripe,...