The final debate

Barack Obama and John McCain face off for their third and final debate tonight as new polls show the race is slipping away from the Republican candidate.

A CBS News/New York Times poll released Tuesday night found Obama opening up a 14 point lead against McCain in the national race and found that McCain's attacks against Obama had backfired against him. Still, there is a possibility McCain may bring up the name of William Ayers, the former domestic terrorist he has tried unsuccessfully to connect to Obama.

Americans have a much more favorable view of Obama than McCain despite weeks of GOP attacks on the Democrat. Obama holds a statistically significant 8 point lead in the daily survey of all national polls conducted by Real Clear Politics. And polls also show that voters feel Obama's campaign has been much more positive than McCain's.

Obama also has a sizable cash advantage over McCain, which he is using in state after state to defeat his rival. The Democratic presidential nominee now holds a lead in the polls in enough states to win a commanding victory over McCain.

With 20 days left in the race, anything could happen and some Democrats are still worried about a Republican "October surprise." But McCain's opportunities to score a "knockout punch" against his opponent are diminishing. Wednesday night's debate at Hofstra University in Hempstead, New York will provide McCain his final opportunity to speak directly to tens of millions of American voters and convince them that Obama is not ready to be president.

The final debate will focus solely on the economy and domestic policy. That poses another opportunity for Obama as voters have said the economy is their number one concern and most see Obama as better suited to handle the economy. Obama got an early advantage when their first debate, moderated by PBS's Jim Lehrer, spent the first 40 minutes talking about the economy instead of national security and foreign policy.

Tonight the candidates will be seated at a table with moderator Bob Schieffer of CBS News.