Whether a Democrat or a Republican is inaugurated in January 2009, the centre of political gravity in the US is well to the left of where it was a decade ago. President George W. Bush’s own contribution to the shift has been negligible. It is the result of long-term, tectonic shifts in political and economic ideology that are affecting all developed countries.

In hindsight, despite the re-election of a conservative president, 2004 was the hinge between eras. The definitions of right, left and centre changed dram­atically between 1932 and 2004, which can be broken into two periods.