For much of the election year, Sen. Rick Santorum has been one of the most embattled Republican senators. And that's the way he remains on election eve. The polling gap between Santorum and Democratic challenger Bob Casey Jr., the state treasurer, had been in the double digits six months ago, and while Santorum has made some gains, he's still behind Casey by between 8 and 15 percentage points. Months ago it seemed as if like Santorum, with his history of winning tight elections at the last minute, might have a good chance of pulling off the victory. Santorum, the No. 3 Senate Republican, attempted to position himself as strong on national security and had underscored his history of bringing federal dollars back to the state. But his staunch support of Bush and the Iraq war as well as his conservative firebrand style led to low approval ratings.

The campaign to re-elect Sen. Rick Santorum is hoping to push the immigration issue into the spotlight in one of the nation's most closely watched races by launching a new television ad and holding a town hall meeting on the issue this week.

A new independent poll released this week says that in the Pennsylvania race for the U.S. Senate, Democrat Bob Casey Jr., the state treasurer, is ahead of incumbent Sen. Rick Santorum by 10 points, 49 percent to 39 percent.

The campaign to elect Bob Casey, the Democratic candidate for Senate in Pennsylvania, is taking aim at Americans for Job Security, a conservative trade association that has been running television advertisements in favor of Republican incumbent Sen. Rick Santorum and negative ads against Casey.

In trying to win over female voters, the campaign to re-elect Sen. Rick Santorum has launched a new strategy, known as "Women for Rick," which includes outreach events, a website, womenforrick.com and even text messaging.