DAN OSBORN, a candidate for the Senate in Nebraska, has a fable he recounts on the campaign trail. First told by a Canadian trade unionist in the 1960s, Mr Osborn’s version goes like this: “It’s a story about a society of mice that happens to be ruled by cats. The mice are just like our society. They go to work every day, they send their kids to school.” And each election, they pick from a crowd of cats to rule them. Eventually, “the mice wake up”. They realise the problem: it is not that “we’re electing the wrong kind of cat”. It is that “we’re electing cats”. Mr Osborn says that what makes him different is that he is “not ashamed to admit that I’m a mouse.”