ABC News’ David Chalian Reports: Sen. Arlen Specter’s path to the Democratic nomination for Senate in Pennsylvania just got a tiny bit easier. The former head of the National Constitution Center Joe Torsella faced up to the political realities of Sen. Specter’s switch to the Democratic Party and announced today that he is ending his candidacy for the United States Senate. "As we’ve all learned, campaigns can be unpredictable," said Torsella in a video message sent to supporters. "At first, I was reluctant to quit something that so many people have thrown themselves into with their whole heart and soul," he added. Mr. Torsella said the campaign would have likely been "negative, personal, and more about Sen. Specter’s past than about our common future" and that he did not want to run that kind of campaign. The day after Sen. Specter announced he was switching parties to try to save his Senate career, President Obama and Vice President Biden welcomed him to the White House and endorsed his candidacy. Gov. Ed Rendell (D-PA) has also rounded up support among Pennsylvania Democrats all in an effort to clear the primary field for Sen. Specter and work to get him elected as a Democrat in 2010. A potential Democratic primary challenger still exists, though. Rep. Joe Sestak (D-PA) remains undecided about challenging Specter. Mr. Torsella had originally issued a statement in the aftermath of Sen. Specter’s party switch that he was going to remain in the race, but taking on the president, the governor, and the bulk of the Democratic establishment proved to be too daunting a task for the largely unknown Democrat. "I’m not going anywhere," Torsella said toward the end of his video message as he made clear he would be seeking other political opportunities in the future. Mr. Torsella does not, however, endorse Sen. Specter — for now, anyway.