Are Specter's Senate days numbered?

When Sen. Arlen Specter of Pennsylvania joined the Democratic Party two months ago, he was fleeing a tough Republican primary. Now, he may face a tough Democratic primary.

Rep. Joe Sestak (D) of Pennsylvania has all but formally announced his candidacy for Senator Specter’s seat, regularly telling interviewers he’s running. On Wednesday, Congressman Sestak told the Wayne County, Penn., newspaper, The Wayne Independent: “I am going to get into the race against Arlen Specter.”

Sestak, a retired Navy admiral, could undercut Specter from two directions – appealing to conservatives with his military background while appealing to progressives with his support for President Obama’s domestic agenda. For Mr. Obama, the pressure on Specter from the left could be a godsend during these next critical months, when the president will need every Democratic vote. Just days after Specter switched parties, he said on “Meet the Press:” “I did not say I would be a loyal Democrat.”

Does Sestak have a chance? Specter is a five-term senator, a seasoned campaigner, and a survivor. Time and again, he has delivered for his state. He has beat back fierce opponents before, as well as serious illness. He also has the backing of President Obama, Vice President Joe Biden, Pennsylvania Gov. Ed Rendell (D), and the state’s other senator, Bob Casey (D).

But all that establishment support for Specter may backfire. Pennsylvanians don't like being dictated to, and polls now show that they're not sure about Specter. In March, before Specter’s April 28 party switch, his job approval rating was 52 percent, according to the Franklin & Marshall College poll. By June it had dropped to 34 percent.

The poll also shows Specter leading Sestak among Democratic primary voters 33 percent to 13 percent, with 48 percent undecided. No incumbent senator wants half his state on the fence about him, however early in the election cycle.

“Republicans deserted him en masse, Democrats don’t quite trust him, and independents worry about what he stands for,” says Terry Madonna, director of the Franklin & Marshall poll.

Still, Sestak faces an uphill battle. He remains largely unknown outside his district, which includes some Philadelphia suburbs and most of Delaware County, and he will have to raise many millions of dollars in a state with some expensive TV markets. Specter can be expected to raise all the money he needs. Sestak has said he doesn’t have to raise as much money as Specter, but he has to raise “enough.”

Another unknown about Sestak is how he will do as a campaigner in a tough race. He unseated a longtime incumbent, Rep. Curt Weldon (R), in 2006, but Congressman Weldon was mired in scandal and President Bush was unpopular, which tilted the playing field toward the Democrat. Sestak had to present himself as a credible alternative, and he did.

For now, nobody rules out a sixth term for Specter.

“He’s like Houdini, he’s a master escape artist of whatever hole you get him in,” says Mr. Madonna. “I don’t think you can automatically say that Sestak rolls over him.”

On the Republican side, former Rep. Pat Toomey of Pennsylvania is so far the only serious contender for his party’s nomination. But no matter who he might face in the general election, the conservative Mr. Toomey would be the underdog in a state that is now solidly blue.