Responding to news that negotiations with the Iraq government will start in January on the withdrawal of American combat troops from Iraq, Senator Clinton is trying to distance herself from the White House position on whether America should leave behind a permanent military presence.

In an open letter to the president, Mrs. Clinton yesterday asked him to promise that he would not agree to lodge American troops permanently in Iraq and reminded him that Congress has already voted to ensure that there is no residual American force left in Iraq when the conflict is brought to its end.

On Monday, the president’s Iraq war tsar, Lieutenant General Douglas Lute, announced a timetable for negotiations leading to the withdrawal of most American troops by the end of President Bush’s term in office in January 2008. But the general suggested the president was looking for a permanent bilateral security arrangement with Iraq that would leave perhaps 50,000 American military personnel in the country.

“The shape and size of any long-term, or longer than 2008, U.S. presence in Iraq will be a key matter for negotiation between the two parties, Iraq and the United States,” the general said.

Mrs. Clinton’s letter demanded that the president declare his intentions towards Iraq. “I am particularly concerned that this document did not contain any explicit reference or language that indicates that the United States will not seek and will not maintain permanent military bases in Iraq,” she wrote.

She reminded the president that “Congress explicitly passed a restriction on the use of any funds to establish any military installation or base for the permanent stationing of United States Forces in Iraq.”

“Given the express will of Congress and the American people to oppose permanent U.S. military bases in Iraq, the failure to include express language addressing this issue in the Declaration of Principles with the Iraqi government is deeply troubling,” she wrote. “To be clear, attempts to establish permanent bases in Iraq would damage U.S. interests in Iraq and the broader region, and I will continue to strongly oppose such efforts.”

Senator Clinton’s opposition to a permanent final agreement to the American led occupation of Iraq that might entail the continued presence of some American troops sits oddly with her previous remarks on the future of Iraq and brings into relief her maneuvering on a subject that preoccupies the left of the Democratic party.

In the MSNBC Democratic candidates’ debate on September 26, Mrs. Clinton implied that even by 2012, a full four years after next November’s presidential election, there may be a continued need for American troops in Iraq and that, if elected, she would give White House blessing to that presence.

“It is my goal to have all troops out by the end of my first term,” she said. “But … it is very difficult to know what we’re going to be inheriting. … I will immediately move to begin bringing our troops home when I am inaugurated.”

She said, though, that there “may be a continuing counterterrorism mission, which, if it still exists, will be aimed at al Qaeda in Iraq. It may require combat, Special Operations Forces or some other form of that, but the vast majority of our combat troops should be out.”

Mrs. Clinton was filling out an argument she had rehearsed in Iowa in July. “As we do bring our troops home, we cannot lose sight of our very real strategic national interests in this region,” she said. “If, in the future, Iraq becomes a breeding ground for exporting terrorists, as it appears it already is … that is a great worry for our country.

“So as we redeploy our troops from Iraq, I will not let down my guard against terrorism. I will devote the resources we need to fight it and fight it smartly. I will order specialized units to engage in narrow and targeted operations against al Qaeda and other terrorist organizations in the region.”

Mrs. Clinton’s public challenge to the president to promise to bring all American troops out of Iraq also appears to contradict a remark she made to a source reporter Ted Koppel described as someone “who held a senior position at the Pentagon until his retirement. He occasionally briefs Senator Clinton on the situation in the Gulf.”

As Mr. Koppel told NPR’s “All Things Considered” on June 11, “She told him that if she were elected president and then re-elected four years later, she would still expect U.S. troops to be in Iraq at the end of her second term. We’re talking about just a shade less than 10 years from now.”

Nor does her letter to the president reflect the opinions she expressed in an interview with the New York Times on March 16. The opening of the story read, “Senator Hillary Rodham Clinton foresees a ‘remaining military as well as political mission’ in Iraq, and says that if elected president, she would keep a reduced military force there to fight Al Qaeda, deter Iranian aggression, protect the Kurds and possibly support the Iraqi military.”

When asked how many troops she would leave in Iraq, she demurred, “saying she would draw on the advice of military officers.”