WASHINGTON (CNN) - Pennsylvania Sen. Arlen Specter called his fellow Democrat, Rep. Joe Sestak, a "flagrant hypocrite" and accused his rival of registering as a Democrat "just in time to run for Congress."
Sestak has said that he will challenge Specter, who has the backing of President Obama and party leaders, for the Democratic Senate nomination next year. Specter, a longtime Republican, switched his party registration to Democrat this year.
On Thursday, Specter's campaign sought to bring into question Sestak's roots to the Democratic Party. Specter's campaign sent out a list of Sestak's voting history in Delaware County, which the senator's campaign said showed that Sestak registered as an Independent in 1971, didn't vote in any primary elections from 1971-2005 and that he officially registered as a Democrat in February of 2006. Sestak was elected as a Democrat to the House in 2006.
"Congressman Sestak is a flagrant hypocrite in challenging my being a real Democrat when he did not register as a Democrat until 2006 just in time to run for Congress," Specter said in the statement. "His lame excuse for avoiding party affiliation, because he was in the service, is undercut by his documented disinterest in the political process."
Update, 7:11 p.m.: In a statement given to CNN, Sestak defended his record, saying he was an Independent while he served in the Navy because he believed that "military officers should be nonpartisan." He said he voted numerous times by absentee ballot, but that it is "all too common" for military votes to go uncounted because they arrive late.
"We've learned today that Arlen Specter can abandon his party, but he just cant quit making Republican swift-boat attacks on the integrity of Democrats who served in our military," Sestak also said in the statement. He added, "My question to Arlen Specter is this: do you regret voting for George Bush and John McCain? Why should Democrats support someone like you who actively campaigned as recently as last year for politicians with values like George W. Bush?"