The Iraq Study Group is charged with correcting the US course in Iraq in a manner that will be broadly acceptable to the ruling Republicans and the opposition Democrats.
The US military faces a crossroads for its Iraq strategy
The bipartisan panel's influence became apparent as clamour for a change in Iraq policy climaxed in a mid-term poll defeat for the Republicans.
A panel member, former CIA boss Robert Gates, was nominated to replace Donald Rumsfeld, who quit as defence secretary after the election.
And weeks before the report was to be released, the White House appeared to endorse one of its expected recommendations by saying it was ready for talks with Syria and Iran.
President George W Bush has thanked the group for lending its "expertise and knowledge to help our country".
George Packer, a journalist interviewed by the group, said the Bush administration was looking to its report to decide its policy in Iraq.
"Such is the paralysis of official Washington that the course of the war seems to be waiting for the report," he wrote in the New Yorker magazine.
Seeking a compromise
In preparing the report, the panel has interviewed leading Iraqi politicians, current and former US government officials, as well as bureaucrats and experts from across the political spectrum.
IRAQ STUDY GROUP MEMBERS
James Baker, co-chairman, Secretary of State under President Bush Sr
Lee Hamilton, co-chairman, ex-congressman (Democratic) who co-led 9/11 inquiry
Lawrence Eagleberger, Secretary of State under President Bush Sr
Vernon Jordan, adviser to President Clinton
Edwin Meese, Attorney General under President Reagan
Sandra Day O'Connor former Supreme Court justice
Leon Pannetta, Chief of Staff for President Clinton
William Perry, Defence Secretary under President Clinton
Charles Robb, former Senator (Democratic)
Alan Simpson, former Senator (Republican)
The Iraq Study Group's members are veterans of Washington politics, with long experience of serving in the judiciary and legislature or government.
At the panel's head is James Baker, who served as secretary of state under the current president's father, George Bush senior.
He is regarded as an old-fashioned pragmatic conservative - loyal to the president and to the Republican Party but not associated with the neo-conservative ideologues who were among Mr Bush's closest advisers during the early phase of the Iraq campaign.
According to reports of a speech Mr Baker gave at Princeton University, he does not accept the neo-conservative goal that Iraq could become a regional bulwark for democracy.
"We ought not to think we're going to see a flowering of Jeffersonian democracy along the banks of the Euphrates," the Daily Princetonian quotes him as saying.
At the same time, Mr Baker rejects the demand voiced by many Democrats for a speedy withdrawal of US troops.
"If we picked up and left right now," Mr Baker told US TV network ABC, Iraq would face "the biggest civil war you've ever seen".
The most senior politician in the Iraq Study Group after Mr Baker is the former Democratic Representative for Indiana, Lee Hamilton.
Mr Hamilton was co-chairman of the 9/11 Commission.
Between them, the two men must point out a path in Iraq that pleases both their parties - a compromise, according to Mr Baker, between "stay the course and cut and run".
As the BBC's Washington correspondent Justin Webb says, the Democrats and the White House both hope to be able to endorse the report and benefit politically.