He was a Democrat before he was a Republican

This is not the first party switch for Sen. Arlen Specter, who was a Democrat until 1965, when party bosses in Philadelphia denied him the opportunity to run for district attorney. He switched to the GOP and won. Mr. Specter has been a slightly left-leaning centrist in his 29 years in the Senate (his lifetime rating from the American Conservative Union is 44.5 per cent), but, like Pennsylvania, has been moving left in recent years (his 2008 ACU rating was 28 percent). JWR