There, in a nutshell, is the new geopolitical reality confronting the US. It can no longer afford to be the world’s policeman. A large slice of the $2.4 trillion cuts package will come out of the defence budget. President Obama is already approaching foreign entanglements more as an accountant than a warrior. Few doubt that if the Americans had been fully engaged in the Libya campaign, Colonel Gaddafi would be long gone. The planned withdrawal from Afghanistan is driven as much by financial considerations as military and political ones. A former Pentagon official has calculated that it is costing $20 billion a year simply to supply air-conditioning to US forces in Afghanistan and Iraq. Such a swaggering, money-no-object approach to military deployments has been a feature of the US in combat since the Second World War. No more, it would seem.