[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2010/images/05/04/art.specter0504.gi.jpg caption="A new poll out Tuesday indicates that Sen. Arlen Specter's lead in the Pennsylvania Democratic primary is shrinking."]
(CNN) - With two weeks to go until Pennsylvania's primary, a new poll indicates that Rep. Joe Sestak is narrowing the gap with Sen. Arlen Specter in the Democratic Senate nomination battle.
According to a Quinnipiac University survey released Tuesday, Specter leads Sestak 47 percent to 39 percent among likely Democratic primary voters, with 14 percent undecided. Thirty-five percent of people who say they have picked a candidate indicate they still may change their mind. Specter's eight-point edge is down from a 21-point advantage in a Quinnipiac poll released April 7.
Specter, a five-term senator, switched parties from Republican to Democrat last spring. At the time of the party switch, he cited the difficulty in winning the Republican primary against Pat Toomey as a factor. Toomey, the Republican candidate in the race, is a former congressman and former head of the Club for Growth, a limited-government and anti-tax organization.
Sestak, a two-term congressman from southeast Pennsylvania, is a former Navy admiral. The ad wars between Specter and Sestak have increased in intensity in the past couple of weeks.
"Sen. Specter switched parties because he was worried about losing in the Republican primary. His big lead among likely Democratic primary voters has disappeared and although he remains ahead, momentum is clearly on Sestak's side at this point," says Peter Brown, assistant director of the Quinnipiac University Polling Institute Brown.
"As a Republican, Specter did well among Democrats, but large majorities of Democrats have been voting against him for 30 years and that might be a tough habit for many of them to break. In addition, Specter's big lead in name identification has begun to erode as Sestak television commercials introduce him to the voters outside his suburban Philadelphia base," adds Brown.
The Quinnipiac University poll was conducted April 28-May 2, with 930 likely Democratic primary voters in Pennsylvania questioned by telephone. The survey's overall sampling error is plus or minus 3.2 percentage points.