Reuters: Stunned by being sidelined in the endgame of the Copenhagen world climate summit, the European Union is debating how to regain influence over the fight against global warming. Should the world’s largest trading bloc and economic area respond to the policy setback and the diplomatic humiliation of the bare-minimum Copenhagen accord by playing Mr Nice, Mr Nasty, Mr Persistent or Mr Pragmatic? The first two options — setting a more ambitious example to others, or threatening …