On New Year's Eve, just 70 days ago, the course of the 2008 presidential campaign seemed reasonably clear. Hillary Clinton would win the Democratic nomination. The Republicans, fractured between cultural, economic and national security conservatives, seemed headed for a long and divisive contest. Now it has turned out the other way round. As for the general election, polls showed voters preferred a Democratic to a Republican president by margins not seen since the 1970s. Now current polls show a roughly even race between John McCain, certified as the Republican nominee in the Rose Garden, and either Mr Obama or Mrs Clinton. How did this come to pass?

Luck and party rules that tend to allocate delegates on a winner-takes-all basis gave Mr McCain the nomination. Luck: Mike Huckabee edged Mitt Romney aside in Iowa, Rudy Giuliani retreated from New Hampshire en-abling Mr McCain to win there, Fred Thompson barnstormed in South Carolina enabling Mr McCain to outpoll Mr Huckabee by 3 per cent, Mr Giuliani collapsed in Florida where Cuban-Americans cascaded to Mr McCain. On Super Tuesday, February 5, winner-takes-all rules enabled Mr McCain to monopolise delegates in the north-east, in Missouri (with a 1 per cent margin over Mr Huckabee) and in 50 of California's 53 congressional districts. After the rivals all withdrew gracefully, the Republicans had a nominee and one with appeal for some voters who voted Democrat in 2000 and 2004.