[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/04/30/art.sestak.gi.jpg caption="Sestak could challenge Specter."](CNN) - A suburban Philadelphia congressman says he has not ruled out a run for the U.S. Senate in Pennsylvania in 2010 - even if that means bucking the Democratic leadership to challenge newly minted Democrat Arlen Specter.
Rep. Joe Sestak, a retired admiral, told CNN that he had paid no mind to the Democratic leadership when he ran for Congress in 2006.
"They said, 'We don't want you in the race,'" Sestak, 57, told CNN's Rick Sanchez. "'We have someone else.' Called me back the next day to say the same thing. I said, 'I wasn't asking. I was informing you.'
"Here's what I believe. The Democratic political establishment in Washington, D.C., can say whatever they want, and we need to listen to it," he said. "But at the end of the day, this decision is going to be made by us, very independent-minded Pennsylvanians. I'm in a district that's 53 percent Republican, 37 percent Democrat. I wouldn't have gotten elected as a Democrat unless they were independent-minded."
Sestak beat 10-term Republican Rep. Curt Weldon in Pennsylvania's 7th Congressional District in 2006, taking 56 percent of the vote to Weldon's 44 percent. The Democrat handily won re-election over Republican challenger Wendell Craig Williams in 2008, taking 60 percent to Williams' 40 percent.
Sestak was critical of Specter's decision to switch to the Democratic Party after polls showed him trailing challenger Pat Toomey, backed by the party's far right wing, by a wide margin.
"Arlen Specter found it was too hard to run against someone. Happens to be not what politics is about," Sestak said. "It's about what are you running for. And I haven't seen his vote is going to change. So, what is he going to run for? If he's got the right answers. He may be the man.
"If he doesn't work, I have not made my final decision."
Sestak said his decision would be made based on Specter's positions on such matters as health care, military transformation and veterans' issues.
Sestak noted President Barack Obama's pledge to campaign for Specter, but said he was "taken" when Obama said he expected Specter to disagree on some issues.
"I think he's that kind of a man that if a Democrat were to disagree, he'd understand," Sestak said.