By Tony Romeo

HARRISBURG, Pa. (CBS) – Incumbent Democrat Bob Casey is vying for his second term as a US Senator from Pennsylvania in a race against Republican Tom Smith.

Similar to polls in the presidential race in Pennsylvania, surveys of the US Senate race show a wide lead once held by the Democrat incumbent has largely dried up, although most polls still show Bob Casey leading, albeit by single digits.

Casey has run what some observers believe has been a cautious campaign, painting his opponent, Republican Tom Smith, as a tea partier.

Smith, a former Democrat and retired coal company executive, was a political unknown when he beat out the GOP-backed candidate in the primary. He has spent millions of his own money to finance his campaign, attacking Casey for allegedly maintaining a low-profile during his six years in the Senate.