A fatigued and hesitant Barack Obama appeared badly rattled when peppered with almost relentlessly hostile questions combined with strident attacks from his rival Hillary Clinton during a televised debate this morning. Mr Obama, who holds a clear national opinion poll lead and seemed to have weathered recent crises before Tuesday's crucial Pennsylvania primary, gave what even his allies said was perhaps his poorest performance of the 21 Democratic debates. He was taken aback by the succession of questions about his recent comments that voters were clinging to religion and guns because they were "bitter", his association with a former member...