“He is not going to conquer all of Ukraine,” Mearsheimer says, of Putin. “It would be a blunder of colossal proportions to try to do that.”Photograph by Adam Berry / Getty The political scientist John Mearsheimer has been one of the most famous critics of American foreign policy since the end of the Cold War. Perhaps best known for the book he wrote with Stephen Walt, “The Israel Lobby and U.S. Fo