Pennsylvania, solidly Democratic for the past two decades, appears to suddenly have come into play -- even though Obama is leading his Republican rival by 49.5 per cent to 44.8 per cent in an average of polls there by the RealClearPolitics website.
But the president's support is drawn heavily from metropolitan areas of Philadelphia and Pittsburgh, and less from more conservative rural areas. Havoc on city streets, if widespread outages continue, might depress turnout and could see Romney gain an edge.
Pennsylvania's 20 electoral college votes could prove crucial in the "every vote counts" tight race to the 270 electoral college votes needed for victory.
Scenting a shift in the air, two Republican super PACs were set to spend some $3.2 million flooding the Keystone State with television ads in a last minute all-out push, the Philadelphia Inquirer said.