A NEWSWEEK poll this weekend showed Barack Obama storming into a 15-point lead over John McCain, the Republican candidate, but his campaign remains haunted by the damaging and persistent smear that he is a secret Muslim.

His Kenyan older half-brother, Malik, inadvertently added fuel to the fire last week when The Jerusalem Post reported that he had told Israel Army Radio in an interview that “if elected his brother will be a good president for the Jewish people despite his Muslim background”.

Conservative websites and blogs supporting Hillary Clinton spread the news that “Obama’s brother outs him as a liar and a one-time Muslim” accompanied by a picture of Obama and Malik in traditional “Muslim” - African - dress. Cable television news channels repeated the allegations, even though Malik Obama had said nothing of the kind.

What he did say was, “I don’t think Israel should worry too much, you know, about the connection. Because I am Muslim myself and I don’t think that my being a Muslim has got anything to do with my brother being president of the United States.”

It was precisely the kind of misinformation for which the website Fight the Smears was founded this month by Obama’s campaign. A leading item on the site reads: “Senator Obama has never been a Muslim, was not raised as a Muslim and is a committed Christian.”

Yet the rumour refuses to die. In a Wall Street Journal/NBC poll 13% of respondents said they believed he was a Muslim. This was five percentage points more than at the beginning of the year when e-mails claiming falsely that he had attended a “radical mad-rasah” - an Islamic school - in Indonesia spread on the internet.

Obama last week suggested concern about false allegations was a reason for rejecting public financing of his presidential campaign, which would restrict the total he could spend. He said he needed his own resources to counter lies, citing a minor television advertisement in South Dakota that “took a speech I had made extolling faith and made it seem as if I had said that America was a Muslim nation”.

It was a convenient excuse, perhaps, for a candidate who has shattered all records by raising $287.5m (£145m) in the course of his campaign, yet it also high-lighted a genuine fear. The “bounce” in the polls may not last - at this point in the electoral cycle in 1988, Michael Dukakis, the Democratic presidential nominee, held a 54%-38% lead over George H Bush, and in 2004, John Kerry was six points ahead of George W Bush.

News of Malik Obama’s interview emerged as overzealous volunteers in the Obama campaign refused to allow two Muslim women supporters wearing hijabs to ascend the platform behind him at a rally in Detroit. A campaign volunteer reportedly cited “the political situation” as the reason.

Obama apologised by telephone to Shimaa Abdel-fadeel and Hebba Aref, the two women, and said such behaviour had “no place” in his campaign. However, the Council on American-Islamic Relations went on to demand that he invite them on to his platform at a future campaign event. It is a no-win situation for Obama because every time he denies he is a Muslim, he offends people who are.

Artur Davis, an Alabama congressman and leading supporter of Obama, first realised last year the rumours were more than just a nuisance. He said then: “The biggest problem here is that people think he is a Muslim, but the answer was, ‘That’s just crazy’.”

Davis noted that the only “upside” of the controversy about the Reverend Jeremiah Wright, Obama’s radical former pastor in Chicago, was that it showed Obama was a Christian.

Yet Michael Bloomberg, the billionaire Jewish mayor of New York, felt obliged to call on a Jewish group in Florida, a crucial swing state, to denounce the e-mail smears only last week.

Larry Sabato, professor of politics at the University of Virginia, believes that some people are using the rumours as a cover for their discomfort at electing an African-American president.

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