One of the most anti-war potential contenders for the presidency in 2008, Senator Feingold of Wisconsin, is taking himself out of the running for the White House, even as two other senators are reaffirming their interest.

Mr. Feingold, 53, said his decision not to run this time was prompted in part by the Democratic victory in the congressional elections last week and in part by a recognition that he may not be the most charismatic campaigner.

“While I’ve certainly enjoyed the repeated comments or buttons saying, ‘Run, Russ, Run,’ or ‘Russ in ’08,’ I often felt that if a piece of Wisconsin Swiss cheese had taken the same positions I’ve taken, it would have elicited the same standing ovations,” Mr. Feingold wrote in a letter sent yesterday to his supporters.

Mr. Feingold, who was first elected to the Senate in 1992, said he is excited about the opportunities the new Democratic majority will give him to exert influence over the budget, foreign policy, and other issues. “I cannot muster the same enthusiasm for a race for President while I am trying simultaneously to advance our agenda in the Senate,” he said.

Mr. Feingold scored toward the back of the pack in opinion polls, drawing the support of between 1% and 3% of Democratic voters, though he drew strong backing from left-wing bloggers and anti-war activists. “I would strongly prefer that our nominee in 2008 be someone who had the judgment to oppose the Iraq war from the beginning,” the senator said yesterday. Senator Clinton does not fit that bill. She voted for the war, as did nearly all of the other senators considering presidential bids.

Senator Obama of Illinois, who was elected after the initial Iraq war vote, has opposed the war and could pick-up some of the war’s most ardent opponents. However, Senator Kerry of Massachusetts, who is considering another presidential bid in 2008, is pressing a withdrawal plan that Mr. Obama has rejected as too aggressive.

During separate appearances on Sunday talk shows, Senator Biden of Delaware said he plans to seek the Democratic nomination and Senator McCain of Arizona said he is likely to enter the Republican field.

“I still plan on running,” Mr. Biden told ABC’s “This Week.”

On NBC’s “Meet the Press,” Mr. McCain said he planned to talk further with his family about a presidential bid, but when pressed about whether he will start an exploratory campaign committee, he said, “I think so.”

While most recriminations over last week’s election have taken place on the Republican side, there has been some grumbling from Democrats that the party should or could have picked up more than the roughly 30 seats it gained. The chairman of the Democratic National Committee, Howard Dean, clashed with other party leaders by lagging Republicans in fund-raising and insisting on financing Democratic operations across the country, even where Democrats stood little chance of winning. The chairmen of the House and Senate Democratic campaign committees, Rep. Rahm Emanuel and Senator Schumer, have gotten more credit in the press for the victories than has Dr. Dean.

A Democratic consultant who serves as a commentator for CNN, James Carville, said Dr. Dean’s so-called 50-state strategy was a mistake. Mr. Carville told the New Republic that Dr. Dean should be replaced with Rep. Harold Ford Jr., the Democrat who lost the U.S. Senate race in Tennessee but is credited with running a strong campaign.

“Suppose Harold Ford became chairman of the DNC? How much more money do you think we could raise? Just think of the difference it could make in one day,” Mr. Carville said.

The proposal sparked fury from left-wing bloggers known as the netroots, who viewed the effort as a putsch by centrist elements in the party.

However, an official with a group of centrist Democrats, the Democratic Leadership Council, rejected Mr. Carville’s idea. The group’s vice president for policy, Ed Kilgore, called the notion “a really bad idea, at a really bad time.”

“James should get off the purge-Dean bandwagon, if indeed that’s what he’s riding, and focus his considerable talents on the very different challenges Democrats will face in 2008,” Mr. Kilgore said.

The idea of ousting Dr. Dean now seems to be stillborn. Mr. Ford has said he is not interested in the job.

Dr. Dean said yesterday that he plans to stay on through 2008. In an interview with Fox News, he emphasized that Democrats succeeded not just in taking the House and Senate, but added six governorships and nine state legislative chambers to the Democratic column

“This is some kind of inside the Beltway silliness,” Dr. Dean said of the talk of his ouster.