Rep. Joe Sestak (D-Pa.) continues to make the case he's the only true Democrat in the primary race with Sen. Arlen Specter (D-Pa.).

He's up with a new 30-second TV ad, titled "Scorecard," that compares their ratings from various Democratic-leaning advocacy organizations. Needless to say, Sestak scores consistently higher. Announcer: "The best Democrat for Pennsylvania's future: Joe Sestak." The ad also notes that recent polls show the candidates as neck and neck.

Perhaps with that in mind, Republican Senate candidate Pat Toomey's camp has shifted its fire toward the congressman. It's started pushing the narrative that Sestak is a liberal extremist.

"Joe is one of the most far-left members of the Pennsylvania Delegation, voting 100 percent with Nancy Pelosi. Pennsylvanians don't want a San Francisco liberal in the U.S. Senate," Toomey spokeswoman Nachama Soloveichik said in a recent statement.