Today 12 leaders of Spain\u2019s Catalonia region go on trial, accused of rebellion. The proceedings will lay bare long-running tensions about democracy and unity. As Amy Klobuchar, a Minnesota senator, joins America\u2019s presidential race, we ask whether her centrist tendencies are an advantage or a handicap. And a retrospective of the photographer Don McCullin\u2019s work reveals extremes of human experience and suffering.