As Democratic heavyweights weigh in tonight on the party’s foreign policy agenda, one freshman lawmaker with strong military credentials — Rep. Joe Sestak (Pa.) — is calling for the Democrats to drop their push for an immediate pullout from Iraq and work with Republicans on a gradual end to the war.

“If we had reached across to the other side of the aisle last year, we might have already begun a redeployment and have less dead, potentially,” Sestak, a former Navy vice admiral, said in an interview earlier this month. “It’s all been about ending or not ending the war by [approving or limiting war funding] rather than a more strategic approach in which we explained to the nation that ending the war was necessary.”

Sestak is quick to say his criticism is not aimed at Democratic leaders, but he added that he believed his party has faltered in making a clear case for ending the war. He said Democrats “could be on the cusp of owning national security issues for generations” if they can a come up with bipartisan approach to Iraq.

Democrats, however, have splintered on the issue. Liberal Members are pushing for a quick pullout, while moderate and conservative Democrats have resisted calls for an immediate withdrawal in favor of gradually pulling out forces. Presumptive Democratic presidential nominee Sen. Barack Obama (Ill.) straddles the fence, suggesting he wants to end the war immediately but also showing some support for a brokered deal with Iraqis that would have most forces withdraw in 2011.

Sestak no longer backs legislation he first introduced on coming to Congress that set a deadline for all U.S. forces to be out of Iraq by the beginning of 2008. He now backs a bill setting a nonbinding goal of gradually withdrawing most forces from Iraq over 15 to 20 months.

“Ending the war in Iraq is necessary, however, how the war is ended is of even greater importance for United States national security, the safety of members of the United States Armed Forces currently serving in Iraq, and stability in both Iraq and the Middle East,” the legislation states.

Sestak, who serves on the Armed Services Committee, concedes his position has shifted, but he said a more “strategic approach” is needed to win Republican support. Congressional Democrats have failed repeatedly to pass bills or amendments seeking to limit war spending because of opposition from Republicans and even moderate and conservative Democrats.

“At times I see there is an almost physical divide between the two parties,” Sestak said, adding that ending the war would require “bringing people together.” While Sestak touts his plan as a bipartisan approach, he has yet to sign on any Republican sponsors.

Sestak won his seat as a fierce critic of the Bush administration’s handling of the war. He served as one of the Navy’s top strategists before being forced to retire in 2005, and in 2006 he saw his candidacy promoted by Democrats, who remain eager to point out that he’s the most senior military officer ever elected to Congress.

The suburban Philadelphia lawmaker, who some have mentioned as a possible challenger to Sen. Arlen Specter (R-Pa.) in 2010, also has parlayed his military expertise into frequent guest appearances on cable news programs. He was an early and ardent backer of the presidential campaign of Sen. Hillary Rodham Clinton (D-N.Y.) and served on former President Bill Clinton’s National Security Council in the mid-1990s.

Sestak has since backed Obama’s campaign, although he admits he’s not among Obama’s core group of national security advisers.

Still, several Democratic lawmakers have suggested Sestak’s views carry weight among House Democrats. “When he speaks, he has the ear of everyone on the committee,” said Rep. Ellen Tauscher (Calif.), a senior Democrat on the Armed Services Committee. Rep. Jim Cooper (D-Tenn.), also a member of the committee, said Sestak has already emerged as as leader on military strategy. “He’s got the expertise. Democrats should welcome his experience.”

Sestak said he hoped to continue to be a spokesman for his party on national security issues. “My belief is that those that have more recent experience and time in the military can help explain why certain [defense] polices” are needed, he said.