There is no mistaking the influence of MoveOn.org, with its 3.2 million members and powerful fund-raising apparatus, within the Democratic Party.
This liberal activist group has come to occupy a prominent seat at the table among the party elite, so much so that Republicans leaped at a chance to hold Democrats and their presidential candidates responsible for MoveOn's positions after it ran an advertisement attacking the credibility of Gen. David H. Petraeus.
MoveOn, which has raised tens of millions of dollars for Democratic candidates since its inception in 1998, clearly enjoys friendly relations with Democratic Party officials. Its leaders have met several times over the year with Speaker Nancy Pelosi and the Senate majority leader, Harry Reid, to discuss policy and strategy on ending the Iraq war.
MoveOn representatives also take part, as co-founders of a coalition of antiwar groups together under the umbrella Americans Against Escalation in Iraq, in a daily conference call with the Democratic leadership staff on Capitol Hill to coordinate efforts.
Despite conservatives' efforts to lump together the grass-roots organization and the party and to force individual Democrats to take responsibility for MoveOn's wordplay on General Petraeus, the top American commander in Iraq, as "General Betray Us" in its advertisement in The New York Times, the relationship between the two is often complicated and, at times, shows visible fractures.
"I think Democrats understand that when we can join forces and work together, it's very powerful," said Eli Pariser, executive director of MoveOn Political Action. "And then when we can't, it's not fun."
This month, MoveOn sent an e-mail message to members asking whether it should start organizing potential primary challenges against Democrats who were not tough enough on the war, a move that upset Democratic leaders. The group plans to announce the results of its survey on Monday.
The group also sent a strongly worded warning in the spring to Democratic leaders on Capitol Hill not to capitulate to the White House as they struggled to come up with a strategy after President Bush's veto of the $124 billion Iraq spending bill that tied the money to a troop withdrawal timetable.
"We felt it was important for Reid and Pelosi to understand, if they were unable to come through to a conclusion that was seen as bold, they were going to lose the faith of a lot of people," Mr. Pariser said.
With its attention primarily focused on Congress, MoveOn has yet to become vigorously involved in the 2008 presidential race, although its members have been encouraged at points to telephone Senators Hillary Rodham Clinton and Barack Obama's offices to keep them in line on Iraq. Next week, it is beginning an advertising campaign against the Republican candidate Rudolph W. Giuliani in Iowa. Mr. Giuliani took out an advertisement yesterday in The Times attacking the group and Mrs. Clinton.
The group has held two online presidential forums, one on Iraq in April and the other on climate change in July. Mr. Obama, of Illinois, came out on top in a straw poll for offering the best hope for leading the country out of Iraq and John Edwards won on climate change.
Mrs. Clinton, of New York, trailed significantly in both.
"Anybody who has 3.2 million people in an organization and can mobilize and raise resources and things, they are going to have a big impact," said Joe Trippi, a senior adviser to Mr. Edwards.
MoveOn has shown a willingness to depart from party orthodoxy on campaigns. Last year, despite party leaders' entreaties, it took an active role in aiding the antiwar candidacy of Ned Lamont, who was trying to unseat Senator Joseph I. Lieberman of Connecticut, then a Democrat supporting the war effort.
Mr. Lamont won the Democratic primary. Mr. Lieberman ran as an independent in the general election and kept his seat.
"It's good for the Democrats to have an engaged and vocal left," said Jenny Backus, a Democratic strategist in Washington. "It's something the Republicans have benefited from in the last couple campaign cycles. It allows Democrats to look moderate. A vocal left keeps the party from drifting toward triangulation."
Democratic leaders in Congress and presidential campaigns said they winced when they saw the MoveOn advertisement. While they may have agreed with its overall point, that the troop buildup has not worked, several Democratic officials said privately that the advertisement had been counterproductive.
They said MoveOn had handed Republicans a fresh talking point to criticize Democrats and turn the focus from Iraq in a critical week in the war debate.
Senator John Kerry, Democrat of Massachusetts, said on MSNBC that the advertisement was "simply over the top, and I think it's inappropriate, period."
Ms. Pelosi said on "Good Morning America" on ABC that she "would have preferred that they not do such an ad."
Republicans have called on Democratic Congressional leaders and presidential candidates to disavow the advertisement, but they have largely declined.
Several officials said even though the text of in the advertisement might be over the top, public sentiment shared a frustration over the war. Officials said they did not want to play into the Republican Party's hands or anger MoveOn members.
Copyright 2007 The New York Times Company