The final debate: McCain's last, best chance

A New York Times/CBS poll now puts Obama's lead over McCain at 14 points. With his back against the wall, the final presidential debate tonight offers McCain the possibility of clawing his way back into the race. The candidates and the moderator (CBS' Bob Schieffer) will sit at the same table in a debate format engineered to be more conversational. Such a format may encourage more direct exchanges and improvised arguments (both distinctly lacking in the previous debates).

The onus rests on McCain to take the debate by the horns. Will he eschew the negative tactics that have supposedly contributed to his slump in the polls, or will he bring up the bogeymen of William Ayers and Jeremiah Wright? How will he defend his proposed economic policies when a majority of Americans would rather have Obama steering the economy through troubled waters? Can he turn the doddering awkwardness of his last appearance into controlled and comfortable authority?

Obama is likely to continue performing as blandly as he has in the prior clashes, boring his way to a favourable-looking draw. In McCain lies the potential for pyrotechnics. The debate kicks off at 02.00 BST, tune in to openUSA for real-time commentary and analysis on our live-blog.