Recent difficulties in the military occupation of Iraq have given the Senate Foreign Relations Committee an opening to assert new authority over the Defense Department’s operations in the war zone and eased a longstanding logjam over Pentagon cooperation with the committee.

The Bush administration has entrusted the Pentagon with most aspects of the transition to a sovereign Iraqi government — duties that are ordinarily carried out by diplomats from the State Department, which falls under the purview of the Foreign Relations Committee.

Until recently, though, senior members of the committee have complained of being “frozen out” by Pentagon officials, who ordinarily deal with the Armed Services Committee.

“There certainly were problems in the relationship,” said Andy Fisher, a spokesman for Foreign Relations Chairman Dick Lugar (R-Ind.). “Before the war, in fact, the Pentagon refused to come” before Foreign Relations to testify. “But [things] seem to be better in the last couple of months,” Fisher added.

The shift dates back to mid-April, when armed insurgencies flared up in key cities such as Fallujah and Najaf, and photos depicting the mistreatment of Iraqi prisoners appeared in the international media. The latter event, in particular, provided critics of the Bush administration’s Iraq policy with the leverage they wanted to influence policymaking.

Since then, a parade of senior Pentagon officials, led by Deputy Secretary Paul Wolfowitz, have appeared before Foreign Relations. The committee has also heard from Pentagon comptroller Dov Zakheim and Peter Rodman, the assistant secretary for international security affairs, among others.

Foreign Relations has even summoned Richard Perle, a prominent hawk who is often credited with playing a major behind-the-scenes role in Bush administration policy, particularly in the Middle East.

The military occupation of Iraq has posed difficult jurisdictional issues, mirroring the behind-the-scenes battle between State and Pentagon over control of the rebuilding process.

Lugar and Sen. Joseph Biden (D-Del.), the ranking member on Foreign Relations, have complained that the Pentagon often ignored their requests and would only grudgingly provide senior defense officials for hearings or would make only lower-level officials available. Committee aides said that their requests for Wolfowitz to appear before the panel typically took months to bear fruit.

“They’ve tried to play this game where they only have to come and answer questions from Armed Services,” said Norm Kurz, Biden’s spokesman at Foreign Relations. “It usually takes some arm twisting to get the Pentagon to send their senior-most officials.”

In one episode last year that still rankles at Foreign Relations, the Pentagon told the committee that Gen. Jay Garner — the Bush administration’s first choice to lead the post-war transition in Iraq — was “too busy” to appear at a hearing.

Committee aides say they subsequently discovered that Garner instead chose to spend the time providing reporters with an off-the-record briefing on the occupation at the Pentagon.

This affront led Foreign Relations to cancel an appearance by Andrew Natsios, the director of the United States Agency for International Development, whom the committee had sought to pair with Garner. Instead, the committee summoned independent experts to blast the administration’s post-war policy — a move that only deepened the mutual distrust.

Senior aides on Foreign Relations believe that by resisting summonses from the committee, the Pentagon had been trying to sideline the State Department, by not allowing an open forum in which limits on the Defense Department’s role in the Iraq transition could be debated.

Similar concerns have on occasion bubbled up on the House International Relations Committee. But Lugar, Biden and Sen. Chuck Hagel (R-Neb.) have used their prominence in the media to question the Pentagon’s role in reconstruction and prod the department to answer questions.

Biden, for one, feels that Secretary of State Colin Powell has been responsive to the committee’s requests, even heeding the panel’s advice on some key aspects of the post-war reconstruction of Iraq, but that in the Bush administration, the Secretary of State simply doesn’t make the big decisions on diplomacy, Kurz said. “He does not believe that Powell carries the same weight that he did when he entered this administration three years ago.”

In an interview, Powell Moore, the Pentagon’s chief liaison to Congress, rejected any suggestion that defense officials have ignored the Foreign Relations panel’s attempts at oversight.

“There’s a fine line where defense policy and foreign policy begin and end,” Moore said. “So we are very respectful of [the foreign affairs] committees, and are attentive to them. But they have jurisdiction over diplomacy. The Armed Services committees have jurisdiction over the military.”

The flak from Senate Foreign Relations is not unusual these days. The Pentagon has faced a torrent of criticism from across Capitol Hill since the outset of military operations in Iraq. The main complaint by Members is that the Pentagon has kept them in the dark about important developments on the ground.

Pentagon officials vigorously dispute this contention. But they do say that they have stepped up their Congressional outreach efforts considerably since mid-April, when the discontent over the course of the occupation began to peak.

Over a six-week period, the Pentagon arranged 12 closed-door briefings for Members from Gen. Claude “Mick” Kicklighter, who has been managing the transition in Iraq from the office of the Coalition Provisional Authority at the Pentagon.

In that period, the Pentagon also provided eight staff-only briefings and six conference calls for Capitol Hill press secretaries with Gen. Mark Kimmitt, the military’s chief public affairs officer in Baghdad.

“We take comments like that very seriously — when they say we’re not listening to them, or we don’t pay any attention to them,” Moore said.

“That’s a very common fight,” he added. “You have to work to minimize that.”

To be sure, the Foreign Relations panel’s grasping for oversight has been especially brazen by the standards of Capitol Hill, where chairmen jealously guard the jurisdictions of their committees.

Even Pentagon officials must be sensitive to the impression that they are providing too much access to the “wrong” committees. The House and Senate Armed Services committees have the primary oversight role.

Neither the chairmen of the armed services committees, nor their spokesmen, responded to requests for comment.

But Michael O’Hanlon, a defense expert at the Brookings Institution, said that to the extent that Foreign Relations has tried to claim oversight over the Pentagon, it is because the Bush administration has given the department control over nation-building efforts that would normally be handled by State.

“They put the Pentagon in charge of a mission that is very broad-based,” O’Hanlon said.

Beyond the day-to-day management of the transition, there are also questions of how the American military can be used in a sovereign Iraq and when the deployment can end. Those matters raise diplomatic issues that would naturally draw the attention of Foreign Relations, O’Hanlon suggested.