Sen. Arlen Specter (Pa.) took direct aim at Rep. Joe Sestak (Pa.) for the first time Thursday, calling the two-term Congressman a flagrant hypocrite for challenging him in the Senate Democratic primary. In a statement from his campaign, Specter cited Sestaks past voting history in Pennsylvania in an effort to paint him as a political opportunist who only joined the Democratic Party in order to run for Congress. 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. His lame excuse for avoiding party affiliation, because he was in the service, is undercut by his documented disinterest in the political process.Specter announced earlier this year that he was switching parties to run as a Democrat in 2010 and immediately picked up the support of party leaders and the White House. Claiming to be incensed by his new colleagues party switch, Sestak has all but announced he is going to challenge Specter for the Democratic nomination next year.The Specter campaigns statement Thursday went into detail about Sestaks voting record in Delaware County. Specters campaign cited official records on file at the Delaware County Office of Voter Registration in charging that Sestak missed voting in 12 of 35 general elections from 1971 to 2005.He did not vote from 1989-99, missing President [Bill] Clintons 1996 election despite working in the White House at that time as well as missing the 1992 Presidential election, Specter said. Specters campaign cited an Associated Press story this week in which Sestak said he registered as an Independent during his military career because he did not want to be affiliated with a political party during his service. Records show he registered to become a Democrat in January 2006.This is the first time that Specter had openly attacked Sestak in writing.