In a stunning announcement, U.S. Sen. Arlen Specter of Pennsylvania Tuesday said he was switching his party affiliation from Republican to Democratic.

The move came one month after saying his intention for a 2010 reelection bid was to "run as a Republican on a Republican ticket." He was facing a challenge in the republican primary from former U.S. Rep. Pat Toomey.

In a press conference Specter said elements of the Republican Party were moving too far to the right while also saying he couldn’t win as a Republican in Pennsylvania.

“I have found myself increasingly at odds with the Republican philosophy and more in line with the philosophy of the Democratic Party,” he said at a news conference. He also said, “I am not prepared to have my 29-year record in the United States Senate decided by the Pennsylvania Republican primary electorate.”

While Pennsylvania Gov. Ed Rendell and Philadelphia Mayor Michael Nutter – both Democrats -- reacted favorably to the news, other reactions are less favorable.

U.S. Rep. Joe Pitts, R-13, of East Marlborough expressed disappointment in his brief official statement.

“I am deeply disappointed that Senator Specter would choose to align himself with so many of the irresponsible policies we are seeing the Democrats attempting to implement in Washington.  From a trillion dollar energy tax, to government-run healthcare, to a $3.6 trillion budget and deficit spending as far as the eye can see, I am saddened that Senator Specter has chosen to align himself with the party that has brought us these kinds of irresponsible policies.”

No statement was immediately forthcoming from U.S. Rep. Joe Sestak, but the Democrat from the 7th Congressional District did appear on The Ed Show MSNBC.
He said Specter found it “too hard to run against” an opponent in the 2010 Republican primary.

Sestak asked rhetorically, “What’s he running for.”

He added that running for office was “not about keeping one’s job.”

Sestak is considering a run for the senate seat currently held by Specter.

Sestak finally did release a statement, basically reiterating his comments from the day before:

“This may be good for Arlen, politically; however, two key questions need to be answered. First, after 31 years in the military, I learned that you run for something, not against someone. Arlen has made a decision to leave a race because he could not win against someone. What needs to be known is what he is running for,” Sestak said.

“Second, I watched then-Gov. Clinton and then-Sen. Obama take a leadership position in the Democratic Party and shape it. The leadership that would have been most impressive would be if Arlen had used his role to reshape the Republican Party that he said he had entered when it was a ‘big tent,’ but now is leaving because it has gotten too small. In short, I believe that the principles of what he is running for and his commitment to accountable leadership are questions that still need to be addressed.”

Peter Jesson, the chairman of the Chadds Ford Democratic Party noted the political survival factor in Specter’s decision.

"Senator Specter was in a difficult situation; earlier he had won a very close primary over an extremist opponent. Since then, 200,000 moderate Pennsylvania Republicans have defected to the Democratic Party. Facing the same opponent in the 2010 Primary would almost certainly have resulted in defeat. If Specter wished to continue his career, he had no alternative,” Jesson said.

We were unable to reach Mary Kot, the Republican Party leader in Chadds Ford for comment.
 
Toomey, in a Washington Times op-ed piece on Wednesday said, "Mr. Specter began his political career as a Democrat, switched to the Republican side out of political convenience and has switched back for the same reason. On issue after issue, he has changed his position over the years to benefit his political calculations,” Toomey said. "... By switching parties, Mr. Specter guarantees the very thing he has vocally warned against: a one-party Democratic monopoly of the federal government.

"Just a few months ago, Mr. Specter said avoiding one-party dominance was vital for our country. He was right then. Unfortunately, his desire for political self-preservation trumped his previously stated view of the vital interests of our country."

Specter is five-term senator, first elected to the Senate in 1980.  He is the longest-serving U.S. senator from Pennsylvania.

He served as an assistant district attorney in Philadelphia as a Democrat, but came to national prominence when he served as an assistant counsel for the Warren Commission investigating the assassination of President John F. Kennedy. It was in that capacity when Specter came up with what is called the “single bullet theory.” That theory holds that the wounds to President Kennedy and to Texas Gov. John Connally were caused by the same bullet.