WASHINGTON, March 16 : Lacking a clear route to the selection of a Democratic presidential nominee, the party’s uncommitted superdelegates say they are growing increasingly concerned about the risks of a prolonged fight between Senators Hillary Rodham Clinton and Barack Obama, and perplexed about how to resolve the conflict.

Interviews with dozens of undecided superdelegates—the elected officials and party leaders who could hold the balance of power for the nomination—found them uncertain about who, if anyone, would step in to fill a leadership vacuum and help guide the contest to a conclusion that would not weaken the Democratic ticket in the general election.

While many superdelegates said they intended to keep their options open as the race continued to play out over the next three months, the interviews suggested that the playing field was tilting slightly toward Obama in one potentially vital respect. Many of them said that in deciding whom to support, they would adopt what Obama’s campaign has advocated as the essential principle: reflecting the will of the voters.

Obama has won more states, a greater share of the popular vote and more pledged delegates than Clinton.

A New York Times survey of superdelegates last week found that Obama had been winning over more of them recently than Clinton had, though Clinton retained an overall lead among those who have made a choice. Over the past month, according to the survey, Obama picked up 54 superdelegates; Clinton picked up 31.

“If we get to the end and Senator Obama has won more states, has more delegates and more popular vote,” said Representative Jason Altmire, Democrat of Pennsylvania, who is undecided, “I would need some sort of rationale for why at that point any superdelegate would go the other way, seeing that the people have spoken.”

Altmire said he was repeating an argument that he made to Clinton during a session at her house in Washington on Thursday night with uncommitted superdelegates.

The interviews were conducted at a time of rising displays of animosity between Clinton and Obama, with Clinton repeatedly arguing that Obama did not have the foreign policy credentials to stand up to Senator John McCain of Arizona, the likely Republican nominee. Several superdelegates said they were concerned that this could hurt the Democratic Party in the fall elections and put pressure on some of them to endorse one of the candidates to bring the contest to a quicker conclusion.

“It would be nice to find a way to wrap it up,” said Representative Chris Van Hollen of Maryland, chairman of the Democratic Congressional Campaign Committee, who has not committed to either candidate. “If the current trajectory of the debate continues, the divisions will make it more difficult for many of our candidates.”

Over all, the interviews with these influential Democrats presents a portrait of a particularly exclusive political community in flux, looking for an exit strategy and hoping they will be relieved of making an excruciating decision that could lose them friends and supporters at home.

“This was everybody’s worse nightmare come to fruition,” said Richard Machacek, an uncommitted superdelegate from Iowa, who said he was struggling over what to do.

In Ohio, Senator Sherrod Brown would seemingly have an easy task. Clinton won his state by 10 points. If the nominating fight had to be resolved by party leaders, wouldn’t he side with her? Not necessarily. “It’s the overall popular vote, it’s the overall delegates, it’s who is bringing energy to the campaign, it’s who has momentum,” Brown said. “It should be wrapped up before the convention, and I think it will be.”

Representative John P. Murtha, Democrat of Pennsylvania, is not wringing his hands. “I don’t see the problem,” he said. “People complain and criticise each other, and then they always work it out.” But Eileen Macoll, a Democratic county chairwoman from Washington State, is expecting something different—and not exactly looking forward to it. “I think it’s going to go all the way to the floor,” Macoll said. “We will take the vote and that will be the nominee. We’re going to see that happen.”