A frantic effort by Senator Obama to defuse a row over the appearance of a homophobic gospel singer at a fund-raising concert appears only to have made matters worse.

Mr. Obama’s presidential campaign hurriedly added to the concert program yesterday an openly gay white minister, the Reverend Andy Sidden, to counteract the bad publicity generated by its decision to invite the Reverend Donnie McClurkin, a gospel singer who has described homosexuality as a “curse,” to headline a fund-raising event on Sunday in Columbia, S.C.

The incident reflects the need for Democratic candidates to juggle the often conflicting demands of their supporters. Mr. Obama stands accused of trying to win the support of socially conservative evangelical Christian African-Americans, who make up half of the registered Democratic voters in the early voting state of South Carolina, at the expense of gays.

Nor is the Illinois senator the only candidate to find himself in the crossfire between opposing elements of the Democratic voting bloc. Senator Clinton came in for similar criticism when she was endorsed by Harold Mayberry of the First African Methodist Church in Oakland, Calif., who once compared homosexuals to thieves.

Mr. Obama’s campaign went into crisis mode yesterday, with his advisers on the homosexual community at the center of the storm. The senator personally fielded complaints from prominent gay donors and urged the president of the powerful gay rights group the Human Rights Campaign, Joe Solmonese, not to condemn him.

Similar complaints from prominent gay supporters were answered by his deputy campaign chief, Steven Hildebrand, and the University of Pennsylvania law professor who chairs the campaign’s lesbian-gay-bisexual-transgender policy committee, Tobias Wolff.

However, the hectic efforts to defuse the row were unable to head off a scathing statement by Mr. Solmonese. “I spoke with Sen. Barack Obama today and expressed to him our community’s disappointment for his decision to continue to remain associated with Rev. McClurkin, an anti-gay preacher who states the need to ‘break the curse of homosexuality,'” he said.

Rev. McClurkin, 47, who performed for President Bush at the Republican National Convention in 2004, achieved notoriety by renouncing his homosexuality. From his pulpit in Freeport, Long Island, he speaks of being raped as a child by family members, an experience that he says encouraged him to be gay. He has extended his campaign against homosexuality into what he describes as “predatory gays” in the church.

“From 8 to 28, that was my fight, in the church,” he told “Religion and Ethics NewsWeekly.” “You were in an environment where there were hidden … vultures I call them, that are hidden behind frocks and behind collars and behind … reverends and the deacons, and it becomes a preying ground.”

Now, despite the scoffing of the gay community, he says he is no longer homosexual. “I’ve been through this and have experienced God’s power to change my lifestyle. … I am delivered and I know God can deliver others, too,” Rev. McClurkin told the Washington Post.

The news that Rev. McClurkin would headline Mr. Obama’s “Embrace the Change” tour, and that the tour would include artists such as Mary Mary, a gospel duo that has also disparaged homosexuality, stoked a firestorm among gay and liberal bloggers.

A black political analyst, Earl Ofari Hutchinson, author of “The Emerging Black GOP Majority,” wrote an item on the Huffington Post headed, “Obama should repudiate and cancel his gay bash tour, and do it now.” Todd Beeton, at MyDD.com, asked, “Did Obama just lose the gay vote?”

According to a letter to Mr. Obama from the National Black Justice Coalition’s chief executive, H. Alexander Robinson, leaked to Fox News, the three days of concerts are populated by “gospel music’s most openly homophobic artists; the most volatile of which is the Rev. Donnie McClurkin.”

“Your willingness to share a stage with Rev. Donnie McClurkin is alarming and, frankly, deeply disappointing,” Mr. Robinson said. “Rev. McClurkin has consistently disparaged gay men and lesbians, spread half-truths and unproven theories about our lives and has shown a willingness to work with those who would use the rights of gay Americans as a wedge issue to divide black families for their own cynical political objectives.”

John Aravosis at AMERICAblog remarked that “Sucking up to anti-gay bigots and joining them on stage — no, giving them a stage — is certainly defying conventional wisdom as to how a Democrat becomes president.”

The executive director of the Brooklyn-based Truth Wins Out, Wayne Besen, wrote, “I can’t imagine why the Obama campaign would choose to associate with a man who is so closely identified with hatred and discrimination.”

Mr. Obama was obliged to issue a statement. “I have consistently spoken directly to African-American religious leaders about the need to overcome the homophobia that persists in some parts of our community,” he wrote on Monday.

But his remarks failed to quell the tidal wave of resentment from those who believe he is pandering to ignorance in order to win favor in South Carolina, where, according to a Winthrop poll, 70% of African-Americans dislike the notion of homosexuality.

Mr. Obama’s dilemma was summed up by a member of the Clinton administration, Keith Boykin, in his personal blog.

“If they disinvite McClurkin, they run the risk of offending black voters who are inspired by McClurkin’s message and don’t know or don’t care about the gay controversy. If they go ahead … they run the risk of alienating gay voters who have supported and contributed to their campaign since the beginning,” Mr. Boykin wrote.

As for rushing onto the program Rev. Sidden, a white United Church of Christ pastor in Columbia, S.C., Mr. Boykin appeared doubtful that the trick would work. “Obama won’t win any new black votes by getting a white gay guy to speak at a black event,” he wrote. “Especially when there are plenty of black straight people, black gay people, families of black gay people, and friends of black gay people who could have been chosen to speak.”