Here’s how “the whole collective self-government thing goes down the tube,” according to two historians who have studied the fall of other democracies. As the United States nears its 250th anniversary, two historians of the world’s longest-lasting democracies say the country’s fate may depend on whether Americans can rediscover a declining civic skill: compromise. “We have to figure out a way to compromise, to strike bargains,” Josiah Ober, a Stanford University political scientist, historian,