WASHINGTON — Secretary of State Rice spoke out yesterday against efforts in Congress to limit the role of America’s forces in Iraq, saying President Bush would not allow himself to be constrained by such a “micromanagement of military affairs.”

Asked whether Mr. Bush would abide by a binding resolution, now being drafted by Democratic leaders, that would include the start of troop withdrawal from Iraq, Ms. Rice told “Fox News Sunday” that such a proposal would go against his efforts to support the “flexibility of our commanders to do what they think they need to do on the ground.”

“I can’t imagine a circumstance in which it’s a good thing that their flexibility is constrained by people sitting here in Washington, sitting in the Congress, trying to micromanage this war,” Ms. Rice said. “I just don’t think it’s a good thing.”

She said Army General David Petraeus, the new American commander in Iraq, backs the president’s plan to send 21,500 additional troops to Iraq, primarily to deal with sectarian violence in Baghdad.

The legislation being drafted by Senator Levin, a Democrat of Michigan who is the chairman of the Senate Armed Services Committee, and other Democrats would place new limits on the mission by modifying the 2002 resolution authorizing the use of America’s military force in Iraq.

It would restrict the role of American forces to pursuing Al Qaeda operatives and supporting and training Iraqi army soldiers. It also could set a March 2008 goal for withdrawing troops not involved in those activities.

It is unclear how much bipartisan support Mr. Levin and others have managed to shore up in the Senate since their last effort to pass a symbolic resolution opposing the deployment of additional troops failed this month. A similar measure passed the House.

Ms. Rice, who also appeared on ABC’s “This Week,” said the restrictions in the new proposal were impractical, given the nature of war and counterterrorism in Iraq.

“How do you possibly distinguish what is going on in Baghdad, for instance, from the fight with Al Qaeda?” she told ABC. “Some of these car bombs may indeed be the work of an organization like Al Qaeda or Al Qaeda-affiliated allies.”

Mr. Levin, on NBC’s “Meet the Press,” argued that Congress had “the responsibility — not just the power, the responsibility — to speak out and to change the course when you have a failing course, which is what we’re on in Iraq.”

“This is not a surge so much as it is a plunge into Baghdad and into the middle of a civil war,” Mr. Levin said, adding: “We’re trying to tie the hands of the president and his policy. … The president needs a check and a balance.”

If Congress passes this binding resolution and Mr. Bush chooses to ignore it, Mr. Levin said, “then we have a constitutional battle on our hands.”