This US presidential election has it all: great issues at stake amid an unprecedented economic crisis, unusual and (in different ways) impressive candidates, and more twists and turns than seems at all reasonable. Thursday’s vice-presidential debate upset expectations yet again. After a dismal few days, Sarah Palin, the Republican nominee, had seemed capable of sinking John McCain’s bid for the presidency. In her contest with Joe Biden, she bounced back.

In the end, the Palin phenomenon may be no more than a subplot in this election, but it is a fascinating one nonetheless. Ms Palin, who had served only briefly as governor of Alaska, and before that as the mayor of a small town, emerged from obscurity to receive the nomination. Her speech at the Republican convention in September electrified a party that was none too keen on its presidential nominee, and was almost preparing to lose. Much more than Mr McCain, she stood for social conservatism. The party’s base was delighted.