Barack Obama is preparing to deliver a major address Tuesday on race, politics and unifying the country after being hounded by questions about his relationship to a pastor whose sermons have been laced with anti-American invective.

In a speech whose religious significance could compare to one given in December by former GOP presidential hopeful and Mormon Mitt Romney, Obama may be forced to explain the philosophy of the 8,000-strong Trinity United Church of Christ in Chicago, where the Democratic presidential candidate has been a congregant for 20 years.

In announcing the morning address, to be delivered in Philadelphia, Obama would not say specifically what he will discuss, but suggested he wants to cool down the atmosphere after incendiary remarks by his pastor, retired Rev. Jeremiah Wright Jr., blanketed the airwaves over the past week.

"I am going to be talking about, not just about Reverend Wright but just the larger issue of race in this campaign, which has ramped up over the last couple of weeks," Obama told reporters after a town-hall meeting. "Part of what I'll do tomorrow is to talk a little about how some of these issues are perceived from within the black church community, for example, which I think views this very differently."

Obama has been on defense regarding statements made during Wright's sermons, including calling America the U.S. of KKK-A and saying the nation should be damned for its treatment of blacks. The Illinois senator has claimed repeatedly that he has never been present for any of the vitriolic speeches delivered by Wright, and does not approve of them.

"None of these statements were ones I had heard myself personally in the pews," he told FOX News on Friday, saying that had he "heard them repeated I would have quit."

Obama on Monday said he "strongly" condemns "the statements that were a source of controversy," and called Wright's remarks "wrong." But he also attempted to lay blame at the feet of the media, suggesting those remarks, which have aired on the church's own Web site as well as outlets like YouTube, are being mischaracterized.

"I think the caricature that's being painted of him is not accurate," he said, adopting language similar to a statement from his church issued Sunday.

With the constant attention on Wright, Obama's strategists planned the speech, deciding they could no longer ignore the percolating issues that are distracting from the candidate's message of hope and change.

"Given the events of the past few weeks, and some of the statements that have been made, Senator Obama felt it was an important moment to address the issue of race, politics and how we bring our country together," Obama spokesman Tommy Vietor said Monday.

Not doing anything to deflate the importance of the speech, Obama adviser Jim Margolis said the speech has been written entirely by Obama, who has been up "very late" the last two nights rivising.

Margolis said the controversy over Wright is the entire driving force behind the speech, and the decision to deliver this speech is a reflection of Obama's desire to explain his relationship with Wright, how much Obama disagrees with Wright, and also there is more to Wright than just the sound bites seen and heard across the country in the past week.

"This is his speech, his moment ... , " Margolis said. "People are really paying attention and in a way this an opportunity."

Margolis said no one in the campaign tried to talk Obama out of giving the speech and that the campaign "will take questions" on the Wright story after the speech, but Obama considers the speech a rhetorical end-point to the Wright controversy.

But one Republican Obama critic says don't expect too much from the speech in terms of mending racial divisions.

"It can't be (about improving black-white relations) because not one black man or white man can speak to that issue. Communities have to rise up. So this is about how Barack Obama saves his campaign from the hemmorhaging that has been going on" as more light has been shed on Wright's words, said Michael Steele, chairman of GOPAC, a fundraising organization to put Republicans in local and state offices.

"He's going to come out I think with a lot of the typical Barack, flowery language on race and so forth," said Steele, who was the first black lieutenant governor of Maryland. "But, you know, he's not a racial messiah. This is not one individual solving this question or this crisis that may or may not exist in America."

Meanwhile, Obama's advisers have started talking in the past tense about Wright, who is now reverend emeritus at the church and at least since late Friday is no longer on Obama's African American Religious Advisory Council. The Obama camp has also categorically denied an unconfirmed report that the candidate attended an anti-American sermon of Wright's last July 22. On that day, Obama attended a conference on Hispanic issues in Miami, as did his rival Hillary Clinton.Critics say it matters less whether Obama attended the individual sermons. His long-standing relationship with the church, they say, raises questions about the legitimacy of a campaign that has tried to transcend racial divisions.

"Here's a candidate who claims to be a unifier and yet he belongs to a church where they specialize in denouncing whites," said Ronald Kessler, NewsMax.com political writer. "And the Web site of the church, you don't have to listen to a sermon, the Web site describes the church as being unashamedly black and subscribing to the black value system."

Had John McCain been caught up in a longterm relationship with a controversial pastor, "I don't think that the media, the mainstream media, the dinosaur media, whatever you want to call it, would be engaged in 'Well are we really fairly portraying this pastor?'" said conservative talk radio host Laura Ingraham, responding to Obama's complaint of unfair treatment. "I think this is someone who is in the last refuge" of a story that is spiraling out from under him, she said.

Chicago Tribune columnist Clarence Page said he's been to TUCC and had only positive experiences there. He said he heard a "provocative" sermon while he was there, not like the "God damn America" speech delivered by Wright on the weekend after the Sept. 11, 2001, terror attacks.

"If I had a pastor like this I would go to church more often," Page said, referring to his few visits there.

Obama said he knows people are curious about his outlook, and he will try to wrap it all up in his speech.

"This is why I'm giving a speech about this tomorrow, that will be a lot more wholesome than a press conference. Does that make sense?" Obama asked.