The big story of the US presidential election up to Thursday was how few undecided voters there were. Now the final presidential debate is over, these voters have essentially made up their minds - and it is George W.Bush who should be worried.

If John Kerry is elected the 44th president, it will be because of a single night in Miami, Florida, when he came to debate and Mr Bush came to - well, no one is quite sure. The double-digit lead that Gallup polls, long considered an authority for presidential polling, gave Mr Bush after the Republican convention was fully erased by that fateful 90-minute confrontation.