Senator Clinton’s emergence as the early and perhaps prohibitive favorite for the Democratic presidential nomination in 2008 is fueling anxiety among Democratic strategists and operatives who are worried she would lose to a Republican in the general election.

Recent polling underscores some of those worries. In a CNN/USA Today/ Gallup poll made public yesterday, 51% of voters said they would definitely not vote for Mrs. Clinton if she chooses to run for president in 2008. In a separate nationwide poll conducted this month for a spirits company, Diageo, and a political newsletter, the Hotline, 44% of all voters and 19% of self-described Democrats said they viewed the New York senator unfavorably.

According to Democratic Party insiders, such numbers are adding to skittishness about Mrs. Clinton’s potential candidacy.

“There are a lot of people who are conventional Democrats ideologically who think she can’t win, and we’re caught in this bind where she’s unstoppable and therefore our goose is essentially cooked,” a Democratic consultant and former aide to Senator Lieberman, Dan Gerstein, said.

Many Democrats are reluctant to criticize the former first lady in public. Indeed, Mr. Gerstein, who is no relation to this reporter, quickly added that he does not agree with those who think Mrs. Clinton would be doomed to defeat in November. But he acknowledges that the topic is widely discussed. “I don’t believe that. I don’t buy it, but it’s surprising how often that’s being repeated,” he said.

A former chairman of the South Carolina Democratic Party, Richard Harpootlian, is among those who will own up to such misgivings. “Mrs. Clinton, because of some positions she has taken over the years, gets a visceral reaction to her here, both negative and positive. I’m afraid around the South and Midwest the visceral reaction is not good,” he told The New York Sun.

Mr. Harpootlian said Mrs. Clinton would be bucking long-established trends against the election of a president who was a sitting senator and against candidates from the Northeast, while also seeking to be the first woman elected to the nation’s highest office. “She’s got to blaze all those trails at the same time,” he said.

The South Carolina attorney was almost apologetic about his analysis and stressed that he’s a “big fan” of Mrs. Clinton. “I don’t think there’s any question she’s a very powerful, bright woman, but at the end of the day I want to win in ’08. It’s not about, ‘Do I like her?’ I do,” Mr. Harpootlian said. He recently threw his support behind a former Virginia governor who is also mulling a bid for the Democratic nomination in 2008, Mark Warner.

A former White House chief of staff and budget director under President Clinton, Leon Panetta, conceded a “nervousness” exists in the party about Mrs. Clinton’s general election prospects. He said the perception stems from concerns that her candidacy could cause a return to the bitter political fighting of the Clinton era.

“What people raise is the nervousness about, to some extent, what they went through with the Clintons, particularly in those last few years,” said Mr. Panetta, who now runs a public policy institute in California. “Can she really bring the country together or is she the kind of lightning rod that would stimulate all of the opposition and the kind of ‘hate’ side of the political agenda resurrecting itself, making it an ugly campaign?”

Mr. Panetta also said the corruption scandals swirling around the capital at the moment could tilt the 2008 playing field toward an outsider. “Ultimately, it’s the issue of, do we turn to somebody new? We’ve been through the Clintons, we’ve been through the Gores, we’ve been through the Kerrys – all of whom are known quantities in politics.”

Several members of Mrs. Clinton’s inner circle of advisers declined to be interviewed for this story, citing her public stance that she is focused solely on her re-election bid this fall and has not made a decision about whether to run for the presidency in 2008. However, a political strategist who served as a spokesman for the past two Democratic nominees, Christopher Lehane, disputed the notion that Mrs. Clinton is unelectable. He noted that some of the senator’s critics said she could never surpass a 50% approval rating nationally, but she has done that in several recent polls. “It’s pretty clear she’s in a class by herself,” Mr. Lehane said. “If she was on the ticket in 2004, would a Democrat have won? I think the answer is yes.”

A former chairman of the Democratic National Committee, Steven Grossman, said he tells skeptics of Mrs. Clinton’s chances that she is laying claim to the political center much the way her husband did in 1992 and again in 1996. “I’ve heard those concerns but think Senator Clinton has worked very hard and is working very hard, since the beginning of 2005 and in this campaign, to bind up those wounds,” Mr. Grossman said, a Massachusetts business executive. “I think people will be surprised at how strongly she’s respected in places that aren’t expected,” he said.

Mr. Gerstein said Mrs. Clinton’s difficulties with women voters are a formidable, but surmountable challenge. “A lot of women just don’t connect with her to the point where they’re hostile to her,” he said. “If women aren’t with her as the first viable woman presidential candidate, I don’t see how she beats what Kerry did on the electoral map.”

Analysts said the concern within the party about Mrs. Clinton does not arise from a particular point in the ideological spectrum and is common even among those who support her. “I don’t think it breaks down along ideological fault lines. It’s more along personal and political fault lines,” Mr. Gerstein said. The consultant compared it to the phenomenon in 2004 that led many primary voters who agreed with Howard Dean to vote for other candidates seen as more viable in the general election.

The lack of any ideological agreement among Mrs. Clinton’s Democratic skeptics is a boon to her because it prevents support from coalescing around an alternative. Several Democratic strategists pointed to Mr. Warner, the former Virginia governor, as a plausible counterpoint to Mrs. Clinton. However, the senator’s most vocal opposition at the moment is coming from the anti-war left. For instance, a left-leaning syndicated columnist, Molly Ivins, declared in a recent column that she could not support Mrs. Clinton in 2008. “Enough triangulation, calculation, and equivocation. Enough clever straddling, enough not offending anyone. This is not a Dick Morris election,” Ms. Ivins wrote.

No consultant or strategist interviewed for this story could explain how Mr. Warner, who is generally viewed as more conservative than Mrs. Clinton, could capture the support of liberals passionately opposed to the war. “Those who are running would in many ways split the opposition to her,” Mr. Panetta said.

Another wild card in assessing Mrs. Clinton’s electability is a lack of certainty about which Republican she would face in November. “It’s an awful lot about matchup,” Mr. Lehane said.

Many Democrats and independent analysts believe the most difficult race for Mrs. Clinton would be one against Senator McCain of Arizona. The recent Hotline poll showed Mr. McCain with 47% of the vote and Mrs. Clinton with 32% in such a contest. However, Mr. Lehane said the showdown would be far more competitive because Mr. McCain would have to tack far to the right to win the Republican nomination. “For John McCain to get the nomination he has to be a very different John McCain than we know today,” the consultant said.