The uneasy confluence of sports and politics is featured in a new book by The Nation's Dave Zirin, called Game Over: How Politics Has Turned the Sports World Upside Down.
During the civil rights movement and the Vietnam War, athletes routinely made their political views known. In some cases, that isolated them from sports fans. In other cases, their influence led to real change. But in recent decades, those voices fell silent. Some say the siren's call of endorsement deals made them gun-shy about speaking their minds.