"First order of business is to change the direction of Iraq policy," said Sen. Carl Levin (D-Mich.), who is in line to become chairman of the Senate Armed Services Committee next year when Democrats become the majority party in both chambers of Congress.
Senior White House officials countered that setting timetables for U.S. troop withdrawals would weaken the Iraq government and embolden insurgents, but they acknowledged a need for fresh ideas on Iraq and expressed a new willingness to negotiate with Democrats on an array of foreign policy issues.
White House Chief of Staff Josh Bolten indicated that the president would block legislation calling for a scheduled withdrawal.
"I don't think we're going to be receptive to the notion there's a fixed timetable at which we automatically pull out, because that could be a true disaster for the Iraqi people," Bolten said on ABC's "This Week," one of two Sunday talk shows on which he appeared.
Even so, he added, the White House is "willing to talk about anything" and is prepared to adjust tactics.
The developments came as President Bush and members of his national security team prepared to meet today with a panel of foreign policy experts who have been charged with developing proposals for how to proceed in Iraq.
The panel is headed by James A. Baker III, who served as secretary of State when Bush's father was president, and Lee H. Hamilton, a former Democratic congressman who chaired the House Foreign Affairs Committee.
The urgency of the work of that commission was underscored Sunday by the continuing violence in Iraq, where nearly 100 people were killed in a 24-hour period, including 38 in twin suicide bombings at a police recruiting center, the deadliest strike on a police facility in months. In addition, Iraqi Prime Minister Nouri Maliki harshly criticized fellow lawmakers for placing partisan concerns above the national interest, and he promised major changes in his Cabinet.
The comments by Levin and others offered a glimpse of how the Democrats' control of Congress might alter foreign policy, which has been dominated by Republicans and the Bush administration since the Sept. 11 attacks more than five years ago.
Senior military officials have recently voiced increasing concern that the security benefits of keeping large numbers of troops in Iraq are outweighed by significant downsides to the heavy U.S. presence. Among them are a perceived reluctance by Iraqis to take the lead in stemming the violence as long as U.S. forces are there.
"We have to tell the Iraqis that the open-ended commitment is over and that we're going to begin to have a phased withdrawal in four to six months," said Levin, who also appeared on "This Week."
Levin was joined in his call for a phased pullout by Sen. Joseph R. Biden Jr. (D-Del.), who is in line to become chairman of the Senate Foreign Relations Committee.
Sen. Harry Reid of Nevada, the Democratic leader in the Senate, told NBC's "Meet the Press" that decisions on drawdowns should rest with U.S. military officers in Iraq. Still, Reid said that "we need to redeploy" and that a withdrawal should start within several months.
Given the results of last week's elections, the Baker-Hamilton panel, formally known as the Iraq Study Group, has become a focal point for members of both parties as they seek an upper hand in setting the Iraq agenda. The panel is expected to deliver its findings by the end of the year.
Levin said he hoped the commission would endorse calls for a phased pullout. But Bush is likely to use his meeting with the panel today to make the case for elements of the administration's approach.
Iraq was a key factor in Republican losses in last week's election, with nearly six in 10 voters participating in exit polls saying they disapproved of the war and a majority calling for a withdrawal of some or all U.S. troops.
Even so, it's unclear how far GOP lawmakers will be willing to go to challenge the White House and back calls for a drawdown. Sen. John McCain (R-Ariz.) said Sunday that he still believed the United States needed to send more troops to Iraq to curb sectarian violence and reduce the influence of heavily armed Shiite militias.
"I believe that there are a lot of things that we can do to salvage this, but they all require the presence of additional troops," he said on "Meet the Press."
"The question, then, before the American people is, 'Are we ready to quit?' And I believe the consequences of failure are chaos in the region, which will spread," said McCain, who is widely seen as the front-runner for the 2008 GOP presidential nomination.
Members of both parties said they expected the Baker-Hamilton commission to recommend that the United States hold a conference with representatives from Iraq's neighbors to seek greater cooperation in pacifying the country and creating a stable government.
Biden told ABC that Iran and Syria should be included in such a conference because of their influence in the region.
Baker recently met with an Iranian envoy at the United Nations to discuss the prospects for cooperation.
But a proposal that calls for joint meetings with Syria and Iran would pose thorny diplomatic problems for the administration, which has labeled Iran part of an "axis of evil" and has been reluctant to engage either country.
Bolten stopped short of rejecting such a conference, but made it clear that the White House didn't believe dialogue with Iran and Syria would improve matters.
"I don't think there's been a communications problem. There's been a cooperation problem," he said. "Iran and Syria have been meddling in Iraq in a very unhelpful way."
Iran has ties to Shiite groups in Iraq, has large numbers of intelligence operatives in the country and has been accused of supplying components for bombs that have been used to strike Iraqi and U.S. troops.