While much has been made of Barack Obama’s problems with white working class voters, especially in Appalachia, a more problematic trend may be signs of trouble with Jewish voters, a strong if relatively small part of the Democratic base.

Today’s NYT features Jodi Kantor’s story, “Many Florida Jews Express Doubts on Obama.”

On Thursday, Mr. Obama will court Jewish voters with an appearance at a synagogue in Boca Raton, Fla. A longtime Democratic constituency with a consistently high turnout rate, Jews are important to his general election hopes, particularly in New York, which he expects to win; in California and New Jersey, which he must keep out of Republican hands; and, most crucially, here in Florida, where Jews make up around 5 percent of voters. This is the most haunted state on the electoral college map for Democrats, the one they lost by hundreds of votes and a Supreme Court decision in 2000, and again in 2004.

“The fate of the world for the next four years,” mused Rabbi Ruvi New as his Sunday morning Kabbalah & Coffee class dispersed in East Boca Raton. “It’s all going to boil down to a few old Jews in Century Village,” he added, referring to a nearby retirement community.

Jews, of course, are just one of the many constituencies Mr. Obama must persuade: Latinos, women, working-class whites and independents are vital as well. Thanks in part to enthusiasm from younger Jews, he won 45 percent of the Jewish vote in the primaries (not counting the disputed ones in Florida and Michigan), a respectable showing against a New York senator, Hillary Rodham Clinton. But in recent presidential elections, Jews have drifted somewhat to the right. Because Mr. Obama is relatively new on the national stage, his résumé of Senate votes in support of Israel is short, as is his list of high-profile visits to synagogues and delis. So far, his overtures to Jews have been limited; aside from a few speeches and interviews, he has left most of it to surrogates.

And, frankly, a lot of bizarre rumors linger.

Because of a dispute over moving the date of the state’s primary, Mr. Obama and the other Democratic candidates did not campaign in Florida. In his absence, novel and exotic rumors about Mr. Obama have flourished. Among many older Jews, and some younger ones, as well, he has become a conduit for Jewish anxiety about Israel, Iran, anti-Semitism and race.

Mr. Obama is Arab, Jack Stern’s friends told him in Aventura. (He’s not.)

He is a part of Chicago’s large Palestinian community, suspects Mindy Chotiner of Delray. (Wrong again.)

Mr. Wright is the godfather of Mr. Obama’s children, asserted Violet Darling in Boca Raton. (No, he’s not.)

Al Qaeda is backing him, said Helena Lefkowicz of Fort Lauderdale (Incorrect.)

Michelle Obama has proven so hostile and argumentative that the campaign is keeping her silent, said Joyce Rozen of Pompano Beach. (Mrs. Obama campaigns frequently, drawing crowds in her own right.)

Mr. Obama might fill his administration with followers of Louis Farrakhan, worried Sherry Ziegler. (Extremely unlikely, given his denunciation of Mr. Farrakhan.)

How widespread these beliefs are is hard to measure. But it goes well beyond that.

But the resistance toward Mr. Obama appears to be rooted in something more than factual misperception; even those with an accurate understanding of Mr. Obama share the hesitations. In dozens of interviews, South Florida Jews questioned his commitment to Israel — even some who knew he earns high marks from the American Israel Public Affairs Committee, which lobbies the United States government on behalf of Israel.

“You watch George Bush for a day, and you know where he stands,” said Rabbi Jonathan Berkun of the Aventura Turnberry Jewish Center.

Many here suspect Mr. Obama of being too cozy with Palestinians, while others accuse him of having Muslim ties, even though they know that his father was born Muslim and became an atheist, and that Mr. Obama embraced Christianity as a young man. In Judaism, religion is a fixed identity across generations.

“His father was a Muslim and you can’t take that out of him,” said Ms. Chotiner, 51, who said she would still vote for Mr. Obama, out of Democratic loyalty. “Do I have very strong reservations? Yes, I do,” she said.

Several interviewees said they had reservations about Mr. Obama’s stated willingness to negotiate with Iran — whose nuclear ambitions and Holocaust-denying president trigger even starker fears among Jews than intifada uprisings and suicide bombings. American Jews are by no means uniformly opposed to negotiations with Iran, the leaders of several Jewish groups said, but there is no consensus, and everyone fears that the wrong choice could lead to calamity. Israelis fear Iran “could be the first suicide nation, a nation that would destroy itself to destroy the Jewish nation,” Mr. [Alan] Dershowitz said.

While most of this report is anecdotal, there are some data supporting the trend. The latest Rasmussen poll in Florida shows McCain beating Obama 50-40. More interestingly, “Just 57% of Florida Democrats say they will vote for Obama while 27% plan to vote for McCain. The two candidates are essentially even among unaffiliated voters.” To be sure, part of this is a function of Hillary Clinton supporters who haven’t accepted that Obama will be the nominee yet, combined with some bitterness over how the DNC has treated the state. Regardless, Obama has to view this with some concern.

Dave Schuler, Alex Knapp, Dodd Harris and I talked about this phenomenon in passing on last night’s edition of OTB Radio, mostly inspired by a RealClearPolitics piece by former NYC mayor Ed Koch, a liberal Democrat who backed President Bush in 2004 “saying at the time that I did not agree with him on a single domestic issue, but I did believe he was the only one running who appreciated the threat of Islamic terrorism to American values and Western civilization and was prepared to wage a war to defend those values.” Despite Bush’s horrendous approval ratings, Koch argues history will vindicate him precisely because of his stance on terrorism and, in particular, his staunch support of Israel.

I’m dubious of Koch’s claims on a variety of fronts. But there is likely a strong contingent of “Ed Koch Democrats” out there who vote with a keen eye toward America’s policy toward Israel. That both baffles and concerns me but it’s a reality.