More than 500 Democrats in the Keystone State received an e-mail message last week from Vice President Joseph Biden encouraging them to support recent party-switching Sen. Arlen Specter in 2010.

“Three weeks ago, my friend Senator Arlen Specter added one more feat to his long and impressive career — he became a Democrat,— Biden wrote in the missive. “For more than 25 years, we’ve ridden the train together back to Wilmington and Philadelphia. We’ve had some great debates and discussions on the train — and gotten to know each other so well — that it gives me great pleasure to be able to work even more closely with Arlen now.—

The message was sent by the Democratic National Committee and Organizing for America, the umbrella organization that President Barack Obama’s 2008 campaign infrastructure has been folded into. The e-mail also includes a link that directs recipients to a page dedicated to Specter’s career on the DNC Web site.

Obama and Biden appeared with Specter at a White House news conference the day after he announced his party switch, and national Democrats have pledged to support Specter in his re-election bid.

Specter does not currently have a primary opponent, but Rep. Joe Sestak (D) continues to publicly flirt with challenging him for the Senate nomination.