Democratic Sen. Arlen Specter is tied at 44 percent with likely Republican nominee Pat Toomey, according to a  Quinnipiac University poll released today.
But the incumbent, who became a Democrat earlier this year after four decades in the GOP, holds a commanding lead of 53 percent to 30 percent over Delaware County's U.S. Rep. Joe Sestak among registered Democrats. Sestak is  challenging Specter for the nomination in the May 2010 party primary.
In aother test matchup in the poll, Toomey led Sestak, 40 percent to 35 percent among registered voters.
Overall, only 38 percent of registered voters in both parties said that Specter deserves reelection. But, in an encouraging sign of strength, Specter's approval rating among Democrats, who will decide whether he survives to face Toomey in the fall, stands at 68 percent.
One factor that might be dragging down Specter: President Obama's approval rate in Pennsylvania has dropped to 49 percent. Recent political trends have favored the GOP nationwide heading into the midterm congressional elections.
"Toomey's blank slate in the minds of voters is Specter's best chance to reverse his fortunes," said Peter A. Brown, assistant director of the Quinnipiac University Polling Institute, noting that just over half of voters had enough information about Toomey to express an opinion of him.
The poll was conducted from Dec. 8 through Dec. 14 with 1,381 Pennsylvania voters, and its margin of error is plus or minus 2.6 percent.