First, the polls. Two new polls taken late last week and over the weekend show Sestak has pulled ahead of Specter by as much as 5 points. The current TPM Poll Average shows Specter barely holding onto the lead that was once in the double digits -- he currently leads by a margin of 45.5-40.0.
People privy to internal numbers on both sides wouldn't say whether the public numbers accurately reflect the private ones. But both sides say that the picture of a fast-closing Sestak painted by the public polling is the right one.
Which leads us to the swiftboating. Starting with an ad he launched April 20, Specter has been vigorously attacking Sestak's Naval career, claiming he was relieved of duty. (As the New York Times reported, Sestak was reassigned from the last job he had in the Navy after the man he directly reported to was replaced by someone new. Though the reasons for the reassignment are somewhat murky, Sestak -- and the last boss he had in the navy -- equates them to politics in inside the Navy.)
After Sestak attacked Specter for disparaging his military service, Specter asked Sestak to produce his military records to prove him wrong. Sestak has refused, claiming that Specter's request sounds a lot like the attacks on Sen. John Kerry's (D) Vietnam service during the 2004 presidential race.
Today, Kerry -- a Specter supporter -- weighed in on the controversy. He called on the word to be dropped from the political lexicon before refusing to ask either candidate to stop what they're doing.
"Now, six years later, the term swiftboating is back as an issue in the Senate primary," Kerry said in a statement. "I cannot serve as a referee. That's an issue for the candidates to address and the media to investigate."
The swiftboating claims play right into Sestak's strategy moving ahead. He's gone up with negative attack ads of his own, aimed at reminding voters of Specter's last Senate race, where he squeaked by in a Republican primary thanks to the support of his then-friends George W. Bush and Rick Santorum (Sestak also throws in a shot of Specter with Sarah Palin from the '08 campaign trail for good measure.)
The Sestak line of attack may have been a predictable one, but it's proving to be devastating all the same. Despite the support of the entire Democratic establishment -- including President Obama, who cut a Specter radio ad recently -- Sestak continues his dramatic rise in the polls. Specter's likely to call on his big-name Democratic allies in the final days of the race, hoping to defeat Sestak with the force the Democratic party's GOTV machine.
But the public attachment to the Democratic party on Specter's part might play into Sestak's hands as well. With voters down on the establishment everywhere, Specter may have picked the wrong time to wrap himself in the support of Democrats like Obama and Pennsylvania Gov. Ed Rendell. One Democrat on Specter's side at the state level said he was surprised by by how fast Sestak's closed in, and chalked up the tightening polls to Democrats finally becoming aware that there's an alternative in the race as Sestak's name ID goes up on the back of his TV ads.
Moving ahead, both Sestak and Specter supporters expect the battle to shift to electability. Specter beat likely GOP nominee Pat Toomey in the Republican primary back in '04, and his supporters say he's the only Democrat who keep Toomey out of the Senate a second time.
But public polls are shooting holes in that argument, too. A new Rasmussen poll released today shows Toomey leading Specter by a margin of 50-38 in a hypothetical matchup. When paired up with Sestak, however, the race becomes basically a dead heat with Toomey ahead by a margin of 42-40.