WASHINGTON -- Democratic Senate candidate Sheldon Whitehouse has backed away from his call for a deadline to withdraw U.S. forces from Iraq.

Sen. Lincoln D. Chafee, the only Senate Republican to oppose the invasion of Iraq, has softened his longtime opposition to deadlines for pulling out U.S. forces.

Republican challenger Stephen P. Laffey has shifted his emphasis from support for the war to a demand for Defense Secretary Donald H. Rumsfeld's resignation as "accountability" for what he calls mistakes in the conduct of the war.

With Rhode Island's Senate race in high gear, all three leading contestants have shifted ground on an issue that dominates this year's political landscape.

Stark differences persist among Chafee, Laffey and Whitehouse, but all three have taken steps toward the political middle on an increasingly unpopular war that has produced no voter consensus on how to proceed.

Among the candidates who have officially filed with the Federal Election Commission, only Democrat Carl L. Sheeler, a former Marine, has consistently favored immediate withdrawal of U.S. forces.

Whitehouse, like Chafee and Democratic Sen. Jack Reed, is an opponent of the war. Last year, he agreed with them in opposing firm deadlines for troop withdrawal. Whitehouse is the frontrunner in next week's Democratic primary. Secretary of State Matthew A. Brown, a more aggressive proponent of troop withdrawals from Iraq, dropped out of the Democratic Senate primary race last spring.

In an interview last November, Whitehouse said it would be wrong to pull out the troops on a fixed schedule. He said withdrawal should be a function of how U.S. commanders assess "the situation on the ground," including Iraq's ability to "take care of its own stability."

By the spring, Whitehouse had moved to a flat declaration that all the U.S. troops should withdraw by the end of this year. That position put Whitehouse closer to Brown and other war critics who for months had sought a swift withdrawal.

The new position also set Whitehouse apart from Chafee and the majority of Senate Democrats -- including Reed -- who supported the more cautious approach of avoiding any hard-and-fast deadline for a U.S. troop pullout.

This year's key Senate debate on the issue took place in June, when majorities of both parties joined in defeating Sen. John F. Kerry's measure to require the removal of U.S. troops from Iraq by mid-2007. Whitehouse, while still pressing for the earlier deadline of December 2006, said he would have voted with Kerry, the Massachusetts Democrat.

On a closer vote, the Senate also defeated a nonbinding resolution, cosponsored by Reed, that called on President Bush to set a timetable to begin "redeployment" of an unspecified number of U.S. troops from Iraq by the end of this year. The measure included qualifying language that left it up to the president and his military leaders to decide whether and at what pace a troop withdrawal should proceed. Whitehouse, while preferring the more aggressive Kerry measure, said in June that he would have voted for Reed's as well.

Whitehouse has since moved back toward the political center on the war issue, dropping his call for a specific deadline for pulling out the troops. In television and newspaper interviews over the last two weeks, Whitehouse has said military leaders should set the pace for a pullout, with "troop safety" as the key factor in their decision.

Whitehouse said in an interview last week that he held the same position before and after Brown's departure from the race: a call for a "rapid and responsible" withdrawal that would open the door to diplomatic solutions to the conflict.

It was "the march of time" that changed his December pullout deadline, according to Whitehouse. Whitehouse said he does not now seek a new, later deadline, because a reporter would question him about it if such a date passed without a troop withdrawal.

Democrat Sheeler continues to call for an immediate withdrawal, to be accomplished within six months. He said he would have voted against both the Kerry and the Reed amendments this summer because they would not pull the troops out quickly enough.

Sheeler said the Reed amendment was a "politically safe" way for Democrats to register opposition to the war.

Sheeler has made the war the central issue of his campaign, calling for Mr. Bush's impeachment and accusing the president of lying to build support for the invasion.

Laffey, the only Rhode Island Senate candidate who supported the invasion, has made perhaps the most marked shift in tone, changing his emphasis in recent months to demand "accountability" for the Bush administration's mistakes in prosecuting the war.

Last November, Laffey stressed what he called "the great service" that the United States had done for Iraqis by "liberating" them from Saddam Hussein's dictatorship.

"We are going to have to stay there until we finish the job," Laffey said at the time. Laffey said the Bush administration had made mistakes in prosecuting the war but he refused to offer specific criticisms.

Laffey also said last fall that "any set timetable" for troop withdrawal would be "playing into the hands of terrorists," a position he continues to hold. He has said he would have opposed both the Kerry and Reed resolutions this summer.

But in April, Laffey called for Rumsfeld's resignation as a way of calling the administration to account.

Laffey said the administration went to war on a "worst-case scenario," including warnings about weapons of mass destruction that proved to be wrong. But he said the war has been conducted according to a rosy scenario. For example, he said during an interview last week, the administration did not send enough troops to Iraq.

Chafee, the only candidate with a voting record on the war, said during the debates that his 2002 vote against the war powers resolution now looks like the right vote -- a "vindication" of his position, he has told interviewers.

Chafee opposed the Kerry amendment in June, saying, "I'm not ready to have the legislative body dictate to the executive branch" on questions of military deployments.

Chafee was the only Republican to vote for the Reed amendment, though he downplayed the measure as a modest initiative that did not amount to a significant policy departure.

Chafee acknowledged, however, that his openness to troop withdrawal deadlines represents a change in his viewpoint. He signaled the shift during a debate televised about two weeks ago on Channel 12 (WPRI), when he renewed his call for specific diplomatic initiatives by the Bush administration.

If the administration does not take such steps, Chafee said he may come out in favor of a specific timetable for troop withdrawal. During an interview last week, Chafee said he believes the enterprise in Iraq will fail without such diplomacy.

Therefore, Chafee said it may be necessary to set deadlines for getting out of Iraq.

jmulligan@belo-dc.com / (202) 661-8423