In 1970, Richard Nixon nominated a lacklustre Florida judge and political loyalist named Harrold Carswell to the Supreme Court. He was rejected on the grounds that he lacked the gifts for the job, which stung the Nebraska senator Roman Hruska, a Nixon ally. “Even if he were mediocre,” Hruska complained, “there are a lot of mediocre judges and people and lawyers. They are entitled to a little representation, aren’t they? And a little chance?” The nomination of Alaska governor Sarah Palin as John McCain’s vice-presidential nominee has played out much like a modern-day Carswell nomination. Her detractors call her mediocre. Her supporters call her representative.

That is why her debate on Thursday night against Barack Obama’s vice-presidential nominee, Delaware senator Joseph Biden, was of potentially election-changing importance. It came the day after Senate passage of a financial bail-out bill and the day before the House was due to vote on it. A shining performance would stabilise the McCain campaign, which has fallen in the polls after a week of failed publicity stunts (a “suspension” of his campaign, which was widely seen as an attempt to duck the first presidential debate) and contradictory pronouncements. A stumble might finish off the McCain campaign altogether. That did not happen. But the debate revealed disturbing things about US politics for all that.