“It is difficult to cast a negative vote on someone with the qualifications and background of Dean Kagan, but we have a major problem of institutional standing to find out from a nominee what the nominee thinks on important questions,” Specter said, referring to her title as dean of Harvard Law School.

“I have gone to some length to try to find out more about Dean Kagan. In the absence of being able to do so and to have a judgment on her qualifications, I am constrained to vote no,” he said.

Seven Republicans voted for Kagan, including Sens. Jon Kyl (Ariz.), Tom CoburnThomas (Tom) Allen CoburnFormer GOP senator: Trump has a personality disorder Lobbying World -trillion debt puts US fiscal house on very shaky ground MORE (Okla.) and Orrin HatchOrrin Grant HatchMcConnell names Senate GOP tax conferees Ryan pledges 'entitlement reform' in 2018 Utah governor calls Bannon a 'bigot' after attacks on Romney MORE (Utah).
Specter was also a Republican member of the Senate Judiciary Committee, which declined to take up Kagan's nomination to the U.S. Court of Appeals for the D.C. Circuit in the late nineties. Former President Bill ClintonWilliam (Bill) Jefferson ClintonMueller’s probe doesn't end with a bang, but with a whimper Mark Mellman: History’s judgment Congress should massively ramp up funding for the NIH MORE nominated her to the bench in 1999.  

Recent polls show Sestak has pulled ahead of Specter in the primary race.
 
A new Muhlenberg College poll gives Sestak a four-point lead, 46 percent to 42 percent. A new Rasmussen poll shows Sestak ahead of Specter, 47 percent to 42 percent.
 
Sestak has gained political traction by raising Specter’s ties to prominent Republicans such as former President George W. Bush and former Alaska Gov. Sarah Palin.
 
Sestak launched an ad earlier this month with footage of Bush praising Specter as “a firm ally” he could “count on.”