Defense Secretary Robert Gates wrote to Sen. Hillary Rodham Clinton that a top Pentagon official did not intend to impugn her patriotism by suggesting that her questions about U.S. planning in Iraq boosts enemy propaganda.

At the same time, Gates defended his aide and the author of the letter, Undersecretary for Policy Eric Edelman, calling him "a valued member" who provides "wise counsel and years of experience (that) are critically important to the many pressing policy issues facing the military."

In a three-page letter, obtained by The Associated Press on Thursday, Gates sought to calm a politically stoked exchange between the Pentagon and the Democratic presidential front-runner over planning for the withdrawal of U.S forces from Iraq.

The feud burst into the open last week when Edelman sent a stinging letter to Clinton, a member of the Senate Armed Services Committee who had sought answers in May about how troops, equipment and vehicles would leave Iraq.

Edelman wrote that public discussion of withdrawal "reinforces enemy propaganda that the U.S. will abandon its allies in Iraq" and exacerbates sectarian tensions there. The New York senator said Edelman's answer impugned her patriotism while avoiding serious questions about troop withdrawal plans.

Gates' letter, dated Wednesday, insisted that was not the point of Edelman's missive.

"I emphatically assure you that we do not claim, suggest, or otherwise believe that congressional oversight emboldens our enemies, nor do we question anyone's motives in this regard," Gates wrote.

The Defense secretary both agreed with Clinton that congressional oversight of military planning is needed and at the same time defended Edelman.

"I truly regret that this important discussion went astray and I also regret any misunderstanding of intention," Gates wrote.

"I agree with you that planning concerning the future of U.S. forces in Iraq -- including the drawdown of those forces at the right time -- is not only appropriate but essential," Gates wrote, adding that Edelman also agrees with that point.

"You may rest assured that such planning is indeed taking place with my active involvement," he wrote in the letter.

The weeklong back-and-forth underscored the escalating animosity between the Bush administration and the Democratically controlled Congress in the standoff over Iraq policy, and the center seat the divide holds in the 2008 presidential race.

Clinton's spokesman Philippe Reines said the senator was "disappointed that Secretary Gates does not repudiate Undersecretary Edelman's unacceptable political attack."

Reines added that Clinton welcomes Gates statement that congressional oversight of the Iraq war is essential.

"She continues to believe strongly that there is absolutely no room for impugning the patriotism of those who rightfully engage in congressional oversight," Reines said.

The public feud between the Edelman and Clinton could win her points among anti-war voters and liberal Democrats, a critical constituency in primary voting that has challenged her 2002 vote to authorize the Iraq war.

Facing questions about the war during Monday night's debate, Clinton mentioned the letter and the feud.

Among her top Democratic rivals, Sen. Barack Obama of Illinois has argued that he opposed the war from the start when he was serving in the Illinois legislature. John Edwards, the former North Carolina senator, has disavowed his 2002 vote giving President Bush the authority to oust Saddam Hussein's regime.

Clinton, in a call Friday with reporters, said in response to Edelman's letter that she was "shocked by the timeworn tactic of once again impugning the patriotism of any of us who raise serious questions" about the Iraq war.

She was joined in the call by 2004 Democratic nominee Sen. John Kerry, D-Mass., who accused the Bush administration of making "planning a dirty word and an alien concept."

She also complained directly to Gates in writing, asking if he agreed with Edelman's comments. Edelman is a former aide to Vice President Dick Cheney, and served as an ambassador during the Bush and Clinton administrations.

Military leaders have long acknowledged that they have plans for all contingencies in the Iraq war -- more recently saying they have looked at adding troops, pulling troops out and maintaining current levels.

They have provided no details, and insisted that decisions hinge on the report from Gen. David Petraeus, the top U.S. commander in Iraq, and U.S. Ambassador Ryan Crocker, which is due in September. Both men are to testify before Congress on how the current strategy is working and whether it needs to be revised.