March 13, 2008 -- Sen. Barack Obama's pastor says blacks should not sing "God Bless America" but "God damn America."

The Rev. Jeremiah Wright, Obama's pastor for the last 20 years at the Trinity United Church of Christ on Chicago's south side, has a long history of what even Obama's campaign aides concede is "inflammatory rhetoric," including the assertion that the United States brought on the 9/11 attacks with its own "terrorism."

In a campaign appearance earlier this month, Sen. Obama said, "I don't think my church is actually particularly controversial." He said Rev. Wright "is like an old uncle who says things I don't always agree with," telling a Jewish group that everyone has someone like that in their family.

Rev. Wright married Obama and his wife Michelle, baptized their two daughters and is credited by Obama for the title of his book, "The Audacity of Hope."

An ABC News review of dozens of Rev. Wright's sermons, offered for sale by the church, found repeated denunciations of the U.S. based on what he described as his reading of the Gospels and the treatment of black Americans.

"The government gives them the drugs, builds bigger prisons, passes a three-strike law and then wants us to sing 'God Bless America.' No, no, no, God damn America, that's in the Bible for killing innocent people," he said in a 2003 sermon. "God damn America for treating our citizens as less than human. God damn America for as long as she acts like she is God and she is supreme."

In addition to damning America, he told his congregation on the Sunday after Sept. 11, 2001 that the United States had brought on al Qaeda's attacks because of its own terrorism.

"We bombed Hiroshima, we bombed Nagasaki, and we nuked far more than the thousands in New York and the Pentagon, and we never batted an eye," Rev. Wright said in a sermon on Sept. 16, 2001.

"We have supported state terrorism against the Palestinians and black South Africans, and now we are indignant because the stuff we have done overseas is now brought right back to our own front yards. America's chickens are coming home to roost," he told his congregation.

Sen. Obama told the New York Times he was not at the church on the day of Rev. Wright's 9/11 sermon. "The violence of 9/11 was inexcusable and without justification," Obama said in a recent interview. "It sounds like he was trying to be provocative," Obama told the paper.

Rev. Wright, who announced his retirement last month, has built a large and loyal following at his church with his mesmerizing sermons, mixing traditional spiritual content and his views on contemporary issues.

"I wouldn't call it radical. I call it being black in America," said one congregation member outside the church last Sunday.

"He has impacted the life of Barack Obama so much so that he wants to portray that feeling he got from Rev. Wright onto the country because we all need something positive," said another member of the congregation.

Rev. Wright, who declined to be interviewed by ABC News, is considered one of the country's 10 most influential black pastors, according to members of the Obama campaign.

Obama has praised at least one aspect of Rev. Wright's approach, referring to his "social gospel" and his focus on Africa, "and I agree with him on that."

Sen. Obama declined to comment on Rev. Wright's denunciations of the United States, but a campaign religious adviser, Shaun Casey, appearing on "Good Morning America" Thursday, said Obama "had repudiated" those comments.

In a statement to ABCNews.com, Obama's press spokesman Bill Burton said, "Sen. Obama has said repeatedly that personal attacks such as this have no place in this campaign or our politics, whether they're offered from a platform at a rally or the pulpit of a church. Sen. Obama does not think of the pastor of his church in political terms. Like a member of his family, there are things he says with which Sen. Obama deeply disagrees. But now that he is retired, that doesn't detract from Sen. Obama's affection for Rev. Wright or his appreciation for the good works he has done."

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