For decades, Pennsylvania Democrats loathed Arlen Specter as their Republican foil a moderate who could get elected with a large share of independent votes. Now that Specter has switched parties after fearing a conservative primary challenge, those same Democrats are being asked by Obama to embrace their former foe. Democratic Representative Joe Sestak has promised a tough primary fight, positioning conservative Republican Pat Toomey as a potential upset candidate. Whatever the outcome, it won't come easily for Democrats. A recent Philadelphia Daily News poll found that 47% of the state had an unfavorable view of Specter, who has been doing everything he can to burnish his liberal credentials, while just 28% had a favorable view.