New polling may explain why Barack Obama is concentrating on a slew of traditionally Republican states with less than a week until Election Day.

The AP-GfK polls show Obama leading John McCain in four states President Bush won in 2004. Obama is essentially tied with McCain in two other so-called "red" states.

According to these snapshots, Obama is winning among early voters, favored on almost every issue, benefiting from the country's sour mood and widely viewed as the winning candidate by voters in eight crucial states. They are Colorado, Florida, Nevada, New Hampshire, North Carolina, Ohio, Pennsylvania and Virginia.

The candidates are tied in North Carolina and Florida.

McCain aides insist their own surveys show victory is still possible.

A couple of factors could be in McCain's favor. Some voters remain open to changing their minds, from as low as 4 percent in Nevada to 14 percent in New Hampshire. And the impact of race is hard to measure as Obama seeks to become the nation's first black president.