For more articles like this, check out our Political Pulse section.Eight national presidential polls released Monday put Sen. John McCain (R., Ariz.) behind Sen. Barack Obama (D., Ill.) in the race for the White House Tuesday. McCain loses in every poll by an average of more than seven points, confirming predictions by many pundits of a McCain loss in the popular vote. McCain's only chance for a win would be an unlikely scenario similar to 2000 when President Bush upset Al Gore by winning the electoral college. However, the swing state polls show McCain is in the hole there as well, and any upset scenario forces a focus on the several big states -- Florida, North Carolina, Ohio, Pennsylvania and Virginia. Ohio has served as an accurate predictor of the presidential race since 1960. Despite McCain focusing on the home state of Joe the Plumber, he has fallen behind in Ohio in most presidential polls. The most favorable poll for McCain, conducted by Fox, has McCain tied with Obama. The poll least favorable to McCain's chances, Quinnipiac, has him down seven points. However, the big hurdles for a McCain upset would arise early in the evening. Most McCain upset scenarios involve flipping Pennsylvania from a blue state to a red state. The races in 2000 and 2004 were very close in the state with Democratic nominees Gore and John Kerry prevailing with small margins. Three polls today had McCain behind by more than 10 points, and only one -- Morning Call -- had him down less, at minus six points. A loss here would mean McCain needs to run the table.