McClurkin only sang one song. McClurkin invited himself. Kirbyjon Caldwell & other answers...

[Bluebear]

"Donnie McClurkin only sang a song or two at the Barack Obama "Embrace the Change" events.

But McClurkin, who won a Grammy in 2004 for his gospel music and is also the pastor of an evangelical church in New York, quickly became the star of the night, which was the conclusion of three gospel concerts the campaign held around the state. McClurkin essentially acted as the emcee of the event, introducing the other gospel artists who performed, and then took the stage for the last hour. In between sermonizing, singing, and raving about Obama, McClurkin repeatedly defended himself.

http://blog.washingtonpost.com/the-trail/2007/10/29/post_159.html

Donnie McClurkin is just a fan of Obama's and volunteered to perform at the concerts. You can't blame the Obama campaign for someone who just is a fan of Obama's.

"I just said yes," he said of his invitation by the Obama campaign.

ibid

"Ex-gay" minister Kirbyjon Caldwell is a recent addition to the Obama campaign.

In fact, for all the criticism on the left for President Bush mixing faith with politics, some of the speakers essentially described voting for Obama as akin to a religious cause. "He's more than a conqueror through Jesus Christ," said Kirbyjon Caldwell, a Houston pastor who was on the tour and is backing on Obama.

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Obama made no bones about his disagreement with McClurkin and renounced his views.

In an effort at damage control, Obama's camp released a statement on October 25th saying they were unaware of McClurkin's beliefs and admits the ex-gay's comments on homosexuality are "deeply hurtful and offensive to many Americans" but also states, "at the same time, a great many African Americans share Pastor McClurkin's beliefs. This also cannot be ignored."

http://www.blackvoices.com/blogs/2007/11/16/the-barack-obama-donnie-mcclurkin-debacle/

The Obama campaign knew nothing about McClurkin or Mary Mary's anti-gay views.

When Mary Mary and Donnie McClurkin performed for President George Bush in 2005, there was no uproar. President Bush is staunchly anti-gay marriage, even advocating a Constitutional amendment to ban it. Political strategists argue he won the election on his "Biblical" beliefs. For Obama, the "Embrace the Change" lineup seems contradictory from someone who refers to gays as his "gay brothers and sisters."
Obama's camp repeatedly emphasized they were not aware of McClurkin's beliefs about homosexuality, which begs the question, if they did know of McClurkin's beliefs, would they have hired him anyway?
No one at Obama's campaign headquarters, Obama For America, returned a request for comment.

ibid