This article lays it all out very nicely:
http://dailycaller.com/2012/01/05/the-case-for-santorum-why-barack-obama-should-fear-the-vest/
Rick Santorum has won many tough races. His election to the US House of Reps in 1990 was considered the biggest upset of the year. He was re-elected overwhelmingly in 1992 despite having a new district that was over 60% Democrat.
In 1994 Rick was successfully elected to the US Senate. He was one of only two people to defeat a sitting Senator that year.
In 2000, Rick was successfully re-elected despite being the number one target of Democrats, in a state that has a more than 1 million voter registration advantage for the Democrats.
When Rick lost re-election in 2006, it was the worst environment possible for Republicans. President Bush's approval rating was remarkably low in Pennsylvania. Not only was Rick defeated, but the Republican candidate for Governor lost that race by 20 points, and 4 Republican members of the US House of Reps were also defeated.
Santorum is considered an outstanding debater and will be a formidable opponent for Obama.
