Among those cited by critics are Zbigniew Brzezinski, the national security adviser in the Carter administration; Samantha Power, a Pulitzer Prize-winning author and lecturer at the John F. Kennedy School of Government of Harvard University; Robert Malley, an adviser on Israeli-Arab affairs during the Clinton administration; and George Soros, an international financier who has funded pro-democracy efforts throughout Europe and in recent years became a major supporter of the Democratic Party in the United States.
Fairly or unfairly, each has been on the receiving end of criticism from some pro-Israel activists or Jewish groups over positions viewed as being hostile to the Jewish state.
The Obama campaign acknowledges that it has received advice from the people named in the negative e-mail campaign, describing the meetings with these individuals as a product of Obama's "one America" philosophy of reaching out to all Americans.
But, in the end, campaign officials say, the candidate should be assessed according to his own votes and statements. Besides, they add, the personalities in question do not play any formal role in advising Obama on Middle East issues. That task, they say, falls to a collection of policy experts in good standing with the pro-Israel lobby.
Unlike the Internet attacks falsely painting Obama as a secret radical Muslim, the "adviser" e-mails appear to have struck a chord among some Jewish organizational leaders, in addition to worrying some grassroots voters.
This week, in an interview with Shalom TV, a Web-based Jewish channel, World Jewish Congress President Ronald Lauder said that "if you have an adviser that is not sympathetic to Israel -- not sympathetic to some Jewish concerns -- you have a potential problem."
"If you only have one or two close advisers and they're both anti-Israel," Lauder said, then "it's only a matter of time before the president becomes anti-Israel."
Lauder made no specific reference to Obama, but the comments come at a time when the Illinois senator appears to be the only candidate facing major questions about his advisers on Israel-related issues.
Last week, Malcolm Hoenlein, the professional head of the Conference of Presidents of Major American Jewish Organizations, reportedly told Israeli reporters that the "change" mantra in the current U.S. election -- mostly associated with Obama -- was worrying.
Ha'aretz framed Hoenlein's comments as an expression of concern about Obama's camp, but the Jewish communal leader told JTA that he was speaking generally about this campaign season and the calls for change coming from supporters of several of the candidates in both parties.
In an effort to counter various attacks against Obama going back several months, his campaign has responded with several long e-mails to Jewish supporters. Insiders say response has been positive -- a perception borne out by primary elections exit polls that show Jews trending toward Obama more than other whites in some states.
Even with minimal impact, attacks can still cross the line and are cause for concern, said Dennis Ross, the Clinton administration's top Middle East envoy.
"When you're in the political season, every difference tends to be magnified," said Ross, who has given the Obama campaign advice and who is now a senior fellow at the Washington Institute for Near East Policy, a pro-Israel think tank. "We can have political differences, but it can't lead to demonization."
Much, if not the vast majority, of the material targeting Obama's advisers is distorted and even false.
The campaign notes that its Middle East policy is strictly the province of four individuals, each of them perceived as pro-Israel and three of them Jewish: Dan Shapiro, a longtime activist and bridge between the Jewish organizational leadership and Democratic Party; Anthony Lake, a Clinton administration national security adviser; Eric Lynn, the Obama campaign's Jewish liaison who has lived in Israel; and Dennis McDonough, once the foreign policy adviser to former U.S. Senate majority leader Tom Daschle (D-S.D.), who had impeccable pro-Israel credentials during his time in office.
Of the four regular advisers, only Lake has taken shots from Obama's critics. In an article in the American Thinker -- the online conservative magazine that has been the principle redoubt of Obama-Israel skepticism -- Ed Lasky faults Lake, who recently converted to Judaism, for having worked for the Carter administration and for living in the Berkshires.
Much of the material appearing in a number of Lasky articles and circulating in e-mails is similarly flimsy, especially his attacks on Malley, according to Obama supporters and some former U.S. diplomats.
Like Ross, Malley was a senior adviser to the Clinton administration at the U.S.-Israeli-Palestinian talks at Camp David in the summer of 2000.
Malley has differed with Ross and others over the degree of blame to be assigned over the talks' breakdown -- Ross singles out the late Palestinian leader, Yasser Arafat -- but he does not solely blame Israel. And in public talks in Washington, he emphasizes Israel's security as a critical element in formulating policy.
"He is not anti-Israeli, he is not a fanatic anti-Israeli," Ross told JTA. "To use these tacks is just wrong."
The targeting of Malley led Ross and four other Clinton-era officials to publish an open letter last week defending his record.
"Whatever differences do exist, there is no disagreement among us on one core issue that transcends partisan or other divides: that the U.S. should not and will not do anything to undermine Israel's safety or the special relationship between our two nations," the letter said. "We have worked with Rob closely over the years and have no doubt he shares this view and has acted consistent with it."
Soros, the billionaire philanthropist, has donated to Obama's campaign. He has also been critical of Israel and of pro-Israel orthodoxies, but the Holocaust survivor has cast his criticisms as mindful of Israel's security.
Recently, he considered funding an alternative pro-Israel lobby, one that would more aggressively advocate for a two-state solution, while also maintaining Israel's security needs. Lasky links to a Soros article last year in the New York Review of Books to show that the financier is a "fierce foe" of Israel. In it, Soros describes his thesis as follows: "Military superiority is necessary for Israel's national security, but it is not sufficient."
Despite what Obama supporters and some observers say are distortions and falsehoods, there's enough that would worry parts of the pro-Israel community, particularly the American Israel Public Affairs Committee and its allies.
Brzezinski's time as Carter's national security adviser left a bitter taste among Israelis and pro-Israel activists. They perceived Brzezinski as creating a false dichotomy between Israel's needs and the effort to recruit Middle Eastern states to America's side in the Cold War -- a key point given that his overriding concern in the Carter administration was containing the Soviets.
It didn't help that Brzezinski initially endorsed the views of Stephen Walt and John Mearsheimer, academics who promulgated the thesis that the pro-Israel lobby fundamentally distorts U.S. foreign policy. He later backtracked to a degree, suggesting that their book overstated its case.
The Obama campaign says it does not take advice from Brzezinski, but has accepted his endorsement as a senior U.S. statesman, who says the Illinois senator has the best policy for extricating the United States from Iraq.
Power, the lecturer from Harvard, is a more sensitive problem for the campaign. An expert on genocide who has worked with Jewish activists who press the case that the United States should have done more to stop the Holocaust during World War II, she served for two years on Obama's Senate staff and is a permanent adviser -- but not, the campaign says, on Middle East-related issues.
Still, she has published lacerating criticisms of Israel's first Lebanon war -- although none that would be out of line with Israel's Labor Party. And in a 2003 Soros-funded symposium, she appeared eager to jump to the conclusion that Israel had committed war crimes in the West Bank town of Jenin.
The Obama campaign has rejected efforts to paint her as anti-Israel, although notably, it does not address her writings related to Israel.
"Samantha Power is a Pulitzer Prize-winning author of a book about the evil of genocide, which includes an extensive discussion of the Holocaust, so for this smear e-mail to paint her as anti-Israel is outrageous," said a statement from the campaign that first appeared in the Palm Beach Post in Florida.
Even as they defend Power, Obama campaign officials say she has little say on Middle East issues, confining her advice to issues such as the genocide in Darfur.
U.S. Rep. Robert Wexler (D-Fla.), who is arguably Obama's top congressional backer in Florida, told the Palm Beach Post that the e-mail campaign criticizing the candidate's advisers was a "lie."
"I wouldn't be involved with any candidate," Wexler was quoted as saying, "that didn't recognize Israel as a Jewish state, that didn't reject the Palestinian right of return, and that didn't demand that Hamas reject terror as a condition for talks with the Palestinians."