When Biden was named, Obama's Pennsylvania office put out a release headlined "Obama selects Pennsylvania's third senator." Delaware, south of Pennsylvania, is in the Philadelphia media market. "People know him big time, and everything he does is reported by Philadelphia television," Rendell says.
What's more, Pennsylvania had Republican senators for 26 of the 30 years between 1977 and 2007 — prompting some elected Democrats to turn to Biden for help. "He really handled Pennsylvania for us," says Rep. Paul Kanjorski, who represents the Scranton and Wilkes-Barre areas.
The strongest tie is Biden's abiding affection for Scranton, where he lived until he was 10. In the northeast corner of the state, Scranton is in the middle of swing-voter territory, home to working-class Catholic voters who in the Democratic primaries went solidly for Clinton.
Biden often invokes his blue-collar background with tales of his childhood playmates and uncles talking politics around the kitchen table, and he visits Scranton every year. Last year, he took his 91-year-old mother, Jean Finnegan, to visit the house where the family once lived.
"Scranton never leaves you; it's in your blood," Biden said in an interview published Sunday by the Scranton Times-Tribune. " I don't know, maybe I have a little romanticized view because I love the place so much."
He said his mother, who lives with him, kissed him as he left for Springfield, Ill., to be introduced as Obama's running mate. "Joey, everybody in Scranton'll be so proud," she told him.
http://www.usatoday.com/news/politics/election2008/2008-08-24-obama-biden_N.htmInteresting article covers a lot more...its a nice read.