America is supposed to be the land of opportunity for all. Increasingly, though, its politics can bring to mind Kirchners, Aliyevs and Assads. Once upon a time, US dynasties referred to financiers, industrialists and sports teams. Now, almost as much as in Argentina, Azerbaijan or Syria, they mean presidents. Between 1976 and 2012, not an election went by without featuring either a Bush or a Clinton in the primaries, and in 1992 the families squared off for the White House. What odds against a repeat?

A year ago, the prospect looked unlikely. Hillary Clinton was a visibly exhausted Secretary of State, telling one and all that she intended to retire after Obama’s first term and give herself over to writing and teaching. As for Jeb, “this was probably my time”, he mused wistfully in June 2012, soon after Mitt Romney, had clinched the nomination in one of the weakest Republican fields in memory…

And there’s a further symmetry to a Bush/Clinton rematch. Even in her student days, her peers predicted that if America were ever to have a female president, it would be Hillary. As for Jeb, the smoothest, brainiest and most accomplished of George H W and Barbara Bush’s children, he was always seen by the father as bearer of the family’s political torch.