LeBron James and Jim Brown have a city in common. And like Brown in the 1960s, LeBron is politically active. Both are also iconic figures in African-American sports and cultural history. But that’s where the similarities end. Dave Zirin, sports editor of The Nation and writer of The Edge of Sports, discusses his new book “Jim Brown: Last Man Standing” and how LeBron is finding his own way as keeper of the flame lit by the likes of Brown, Muhammad Ali and Bill Russell.