U.S. Rep. Jason Altmire (D-McCandless) reiterated Tuesday his support of a bill that would allow expanded offshore domestic oil drilling, telling PolitickerPA.com in an interview that despite his earlier opposition, the bi-partisan compromise must be voted on by Sept. 30 to advance the country's energy debate.

The western Pennsylvania congressman received national attention earlier this week when George Stephanopoulos highlighted Altmire's position while interviewing Speaker of the House Nancy Pelosi (D-Calif.). Pelosi has opposed a vote on the bill that would expand oil drilling on the country's coastline, but the "This Week" host quoted Altmire saying that the House "cannot wait any longer" on the measure.

Altmire told PolitickerPA.com that many Democrats, including the 24 who co-sponsored the compromise energy bill, have challenged Pelosi's position, and he said the Speaker of the House knows her stance might soon be toppled by rank-and-file members who will bring t he measure for a vote by Sept. 30.

"Well, I can't speak for her, but I think she realizes she's starting to lose her grip on this issue," he said. "The PR battle has been lost."

The bill in question would permit oil drilling at least 25 miles from the coastline and allow the development of oil shale while siphoning an estimated $1 trillion from the new development to invest in alternative energy.

Altmire previously has said oil companies need to drill on the 68 million acres of land they already have access to.

Although Altmire maintains he hasn't changed his position, his opponent this fall, Republican Melissa Hart, seized the opportunity to call Altmire a "political opportunist" who "will say anything to get elected."

"Signing onto a bill on your way out of Washington for a five-week vacation after weeks of inaction is not leadership -- it's an attempt to save your hide," Hart said in a statement.

Hart is attempting to regain her seat in the 4th Congressional District after losing to Altmire in 2006 and has spent much of her campaign this year painting her opponent as a far-left liberal out of step with the conservative district.

But Altmire said in this case, he's simply trying to move the process along so Congress can address other important energy reforms, such as investment in nuclear and clean coal technology.

"I just think this issue has become such a hot-button issue it has now gotten in the way of an agreement on comprehensive energy agreement," Altmire said.

He also bristled at Hart's accusation that he's flip-flopping.

"I've heard her accuse me of flip-flopping," he said. "Thing is, I'm a representative, and she and others were calling on me to listen to constituents, and that's what I've done here. I'm going to vote the way the vast majority of my constituents want me to.

"I realize that she's probably upset that she won't have this issue anymore to use as a political wedge."