WASHINGTON — Senior Democrats are coalescing behind the view that America should begin withdrawing from Iraq by early 2008, the heart of the next presidential campaign season.

Yesterday, the incoming Senate majority leader, Harry Reid of Nevada, told reporters after an appearance on ABC’s “This Week” that he would even support a surge in troops in Iraq, as President Bush is likely to call for in his new Iraq strategy.

But the increase in troops should only be part of a plan to begin withdrawing them, the senator said. “If it’s for a surge, that is, for two or three months and it’s part of a program to get us out of there as indicated by this time next year, then, sure, I’ll go along with it,” Mr. Reid said.

The incoming chairman of the Senate Foreign Relations Committee, Senator Biden, put it differently yesterday. At a speech in Manchester, N.H., the Delaware Democrat said he would not support “a surge of troops unless it’s tied to some reason for me to believe that they have a political solution.”

The position emerging among the ascendant congressional majority effectively sets a political deadline for the war in Iraq. Until now, the White House has attacked Democratic attempts — such as a plan from Rep. John Murtha, a Democrat of Pennsylvania — to set a deadline for withdrawal. Such a timetable, the White House and its supporters argue, gives the terrorists an advantage because they can wait out the coalition forces.

One tactic Democratic lawmakers have been employing is aligning themselves publicly with what the military’s top generals reportedly are saying in private. On Fox News yesterday, Senator Kennedy, a Democrat of Massachusetts who sits on the Senate Armed Services Committee, said he would not support the troop surge and would go along with the judgment of the commanders in the military, who reportedly do not favor an increase in troop strength.

That tactic dovetails with the approach of the new secretary of defense, Robert Gates, to managing the Pentagon. Mr. Gates sent out his advisers last week to Pentagon personnel and said he would be a hands-off leader, according to one source in the building. “The message was that ideas and policy would bubble up and not come down like snowflakes,” the source, who requested anonymity, said.

One indication of the views of the senior officer corps could be the perspective of one of their most celebrated members. A former chairman of the Joint Chiefs of Staff and former secretary of state, Colin Powell, said on CBS’s “Face the Nation” yesterday that he believed the army was “about broken.” Echoing the assessment of the bipartisan Iraq Study Group, Mr. Powell said the Iraq situation was “grave and deteriorating and we’re not winning, we are losing.”

Despite expressing the view that America should prepare for a withdrawal, Democratic lawmakers have not yet said they will use the power of the purse to bend the president to their wishes. Mr. Reid stressed yesterday that he did not think the troop push would make much of a difference, but he added, “We are going to do everything we can to make sure our troops get everything they need.”

The one area that Mr. Reid said Democrats would use their influence in the budget process is in the use of contractors in Iraq, which he said number nearly 100,000. “We are not going to continually fund these contractors,” he said.

One hawk within the Democratic Party, Rep. Silvestre Reyes of Texas, the incoming chairman of the House Permanent Select Committee on Intelligence, said earlier this month that he would support a troop surge of up to 40,000 troops, but he has not made that support conditional. Mr. Reyes has come under fire for saying Al Qaeda’s members are Shiite, not Sunni, Muslims.