Many people think radically different things about Sarah Palin – arguably the most polarising figure to emerge on the US political stage in years. Yet no one else has served as a more accurate bellwether for the twists and turns of what is the most volatile presidential race in a generation.

When John McCain, the Republican candidate, announced her as his running mate in late August, the 44-year-old “hockey mom” was described as embarrassingly inexperienced – a “small town mayor just a heartbeat away from the presidency”, according to an initial response from the campaign team of Democratic contender Barack Obama.