By CARL HULSE and JEFF ZELENY
WASHINGTON, July 7 — Democratic voters are not the only ones bitter over their party’s failure to use new Congressional power to force a withdrawal of troops from Iraq. Senator Harry Reid, the occasionally obstreperous Democratic leader, is upset as well.
“We haven’t done enough,” said Mr. Reid, a onetime moderate who has evolved into one of the party’s most fervent critics of the war.
That view captures not only Mr. Reid’s sentiment but also the shifting political dynamic on the war, as public frustration remains high, the conflict dominates the presidential campaign landscape and senior Republicans have chosen to break with President Bush even as the administration has urged patience.
Sensing momentum from the new Republican defections, Mr. Reid and other leading Democrats intend to force a series of votes over the next two weeks on proposals to withdraw troops and limit spending. Democrats are increasingly confident they can assemble majority opposition to administration policies.
“It is going to be harder for Republicans to not sign on to something with bite in it, a clear Congressional assessment that change is needed,” said Senator Carl Levin, the Michigan Democrat who is chairman of the Armed Services Committee. “I think it is more likely there will be a majority around here that say we should begin to redeploy some forces by a certain date, and I hope it would be a larger majority.”
The coming debate will provide a showcase for senators from both parties to debate Iraq war strategy. The four Democratic presidential candidates in the Senate are expected to push their own antiwar proposals and views, and contrast their stances with those of Republicans, notably Senator John McCain of Arizona, who has been among the strongest supporters of the war.
In the first round of debates about the war, there was Democratic anxiety about appearing unsupportive of the troops, and Mr. Reid sought to keep a tighter rein on his colleagues who were pushing for the strongest antiwar legislation. But in the shifting environment, Democrats are newly emboldened.
Mr. Reid said he now saw ending the war as a moral duty, and even if the Senate again falls short, he said, he would turn again and again to Iraq until either the president relents or enough Republicans join Democrats to overrule Mr. Bush.
“I think that each time these people vote to continue what’s going on in Iraq it is a bad, bad move for them and a worse move for our country,” Mr. Reid said.
In the six months since he took control as the majority leader, Mr. Reid, 67, of Nevada, has experienced the highs of leading his party and the lows of almost losing a senator to a critical illness and then losing an Iraq spending fight to Mr. Bush.
The Democratic inability to bring quick change, coupled with a Republican backlash to the rejected immigration proposal, has sent Congressional ratings plummeting.
“The Democratic Congress has lower ratings than President Bush,” said Senator Sam Brownback, Republican of Kansas. “You have to try hard to do that.”
Mr. Reid has also been hobbled by his fragile majority, reduced to 50-to-49 because of the extended absence of Senator Tim Johnson, the South Dakota Democrat who has been recovering from a brain hemorrhage since December. With most Senate action requiring 60 votes — the tally needed to cut off debate — much of the legislation that House Democrats rushed through in their 100-hour sprint has bogged down across the Rotunda, mired in seemingly endless procedural votes and Republican objections.
On Iraq, Mr. Reid has led a 49-to-50 minority as Senator Joseph I. Lieberman, the Connecticut independent who caucuses with Democrats, has sided with Republicans on that issue.
As a result, when Mr. Bush refused to sign an Iraq war spending bill that included a timetable for withdrawal, Mr. Reid, with his counterpart in the House, Speaker Nancy Pelosi, saw no alternative in May but to back down rather than open Democrats to charges of cutting off money to troops in the field. The outcome left many Democrats disenchanted.
“Some folks may have anticipated that the war would be stopped the Wednesday after the Tuesday election,” said Senator Jon Tester, Democrat of Montana. “But this is a complex situation that we’ve got in Iraq right now, and I think most of the people understand that we’re going to do the best we can do with what we have to work with.”
Activist groups aligned with the party said they recognized that reality as they put new pressure on wavering Republicans to join with Democrats on the war legislation.
“Senator Reid was not able to get it done, but ultimately it is the Republicans who are obstructing passage,” said Moira Mack, a spokeswoman for Americans Against Escalation in Iraq.
Democrats hoped to drive home that point in the renewed fight, with the annual Pentagon policy measure as the battleground. The leadership has put much of its muscle behind a plan by Mr. Levin and Senator Jack Reed, Democrat of Rhode Island, that would require a troop withdrawal to begin within 120 days of becoming law and require most combat troops out by next spring.
Mr. Reid has also joined Senator Russ Feingold, Democrat of Wisconsin, in pushing a more confrontational approach that would end spending on most of the combat and significantly limit the role of American forces by early next year.
Another coalition of Democrats led by Senators Robert C. Byrd of West Virginia and Hillary Rodham Clinton of New York, who seeks the party’s presidential nomination, is pushing a plan to rescind the original authorization for the war, though it troubles some Democrats, who worry that any associated provision that allows troops to remain even for limited purposes could be interpreted as new approval to keep forces in Iraq.
Senator Christopher J. Dodd of Connecticut, another Democratic presidential contender, is developing a proposal that would call for a troop withdrawal to begin within a month and be completed by next year.
“I think the public is so far ahead of us — certainly the Democrats are — on this issue,” Mr. Dodd said.
Though senior Republicans like Senators Richard G. Lugar of Indiana, George V. Voinovich of Ohio and Pete V. Domenici of New Mexico have called for a change in Iraq policy, they have indicated they are not ready to go as far as the Democrats. Mr. Domenici and other Republicans, including Senators Lamar Alexander of Tennessee and Judd Gregg of New Hampshire, have coalesced around a proposal that embraces the recommendations of the bipartisan Iraq Study Group, which seeks to shift the use of American forces more to a counterterrorism role and sets a goal of a March 2008 withdrawal.
Many Democrats feel those recommendations fall short because they do not include a hard and fast requirement for troop withdrawal. Mr. Reid and his lieutenants were still considering their strategy toward that proposal, which had support from moderate Democrats, led by Senator Ken Salazar of Colorado, and several Republicans.
The war clearly has consumed Mr. Reid. He said his emotions had been stirred by visits to Walter Reed Army Medical Center to meet with gravely wounded troops and his own calls to the survivors of Nevada residents killed in the fighting.
The impact of the wounded was reflected in an e-mail exchange with a staff member, who, during the war financing fight, relayed poll results that found 56 percent of Americans backed the Democrats, but that a sizable 37 percent sided with Mr. Bush.
“May the 37 percent see the pain and suffering I have seen at Walter Reed,” Mr. Reid replied.
