Ocean's Eleven star George Clooney is urging his fellow Hollywood stars to keep quiet when it comes to politics, because he fears celebrity endorsements could wreck their favourite candidates' chances of victory. Democrat Clooney and a number of screen stars have recently come under attack for voicing their political views. And the actor, whose father Nick Clooney was recently defeated in his bid to be elected the congressional representative for Kentucky, has now vowed to be a lot more politically low-key. He says: "My father ran for congress last year. I couldn't campaign for him and I knew I couldn't,...