KIM LAWTON, guest anchor: With major primaries coming up this week (March 4), Hillary Clinton and Barack Obama have been competing for faith-based voters. But for Obama, this was a week of new religious controversy on several fronts. I took a closer look.

Senator BARACK OBAMA (D-IL, in speech): But what I am suggesting is this: Secularists are wrong when they ask believers to leave their religion at the door before entering into the public square.

KIM LAWTON: Barack Obama has long urged the Democratic Party not to run away from religion. He has spoken openly about his own beliefs, and his campaign has employed a vigorous faith-based outreach strategy. Experts say this has earned him support within the religious community, but religion has also generated controversy for him.

This week, Nation of Islam leader Louis Farrakhan joined the ranks of religious leaders offering praise for Obama. Farrakhan called him "the herald of the Messiah." This raised concern among Jewish leaders who have criticized Farrakhan for using anti-Semitic rhetoric.

Barack Obama was asked about it during Tuesday's Democratic debate.

Sen. OBAMA (speaking at Democratic Candidates Debate in Ohio): You know, I have been very clear in my denunciation of Minister Farrakhan's anti-Semitic comments. I think they are unacceptable and reprehensible. I did not solicit this support.

LAWTON: Also this week, a photo circulated around the Internet showing Obama trying on traditional tribal clothing during a 2006 trip to Africa. Another anonymous email campaign falsely suggested Obama is a closet Muslim. The senator has called this "offensive fear-mongering." Obama describes himself as a "committed Christian" and has often detailed his personal religious journey.

Sen. OBAMA (in speech): My father, who returned to Kenya when I was just two, was born a Muslim, but as an adult was an atheist. My mother, whose parents were non-practicing Baptists and Methodists, was probably one of the most spiritual people I knew, and because she grew up with a healthy skepticism of organized religion, so did I.

LAWTON: Then, as a young community organizer, he visited Trinity United Church of Christ in Chicago and became deeply influenced by its pastor, Jeremiah Wright.

Sen. OBAMA (at UCC speech): He introduced me to someone named Jesus Christ, and I learned that my sins could be redeemed.

LAWTON: Obama has been a member of Trinity UCC for more than 20 years.

Dr. ALLEN HERTZKE (Professor of Political Science and Director of Religious Studies University of Oklahoma): I think what's interesting is Barack Obama is a quintessential mainline Protestant, because he comes out of the United Church of Christ.

LAWTON: But that, too, has been a point of controversy. In June 2007, Obama, an announced presidential candidate, addressed the UCC's 50th anniversary General Synod meeting. On Monday (February 25), UCC leaders received notice of an IRS investigation into whether that speech was a violation of tax regulations that could jeopardize the denomination's tax-exempt status. UCC officials insist they did nothing improper and noted that Obama campaign tables were kept outside the arena on a public sidewalk.

Meanwhile, for the past year, the 9,000-member Trinity UCC has come under fire from conservative bloggers and pundits who raise concerns about Pastor Wright's politics. Wright is retiring as Trinity's head pastor. He's been an outspoken opponent of the war in Iraq and a strong critic of Israeli policies toward Palestinians in the West Bank.

Reverend JEREMIAH WRIGHT (Senior Pastor, Trinity United Church of Christ, Chicago): The United Nations has passed resolutions, at least three, that say that's illegally occupied territory. That's the United Nations saying it. Jeremiah Wright says it, he's anti-Semitic. Excuse me?

LAWTON: Critics have also hit Trinity's embrace of black liberation theology, which emphasizes a combination of African heritage and Christianity. Wright alleges that racism is behind at least some of the criticism.

Rev. WRIGHT: The issue is, you got a black man running and you don't like it. And we've got to keep this message before the public. You don't want a black president, he goes to a black church, they preach black theology -- black, black.

Reverend Otis Moss III is taking over Wright's pastoral duties. He sees the negative attention as an opportunity.

Reverend OTIS MOSS III (Pastor, Trinity United Church of Christ, Chicago): You can continue to say what you want, but the truth is, is that our roots are within the African-American community. Our roots are within the message and teachings of Christ, and they have nothing to do with the bloggers and the emails, but everything to do with the love of God.

LAWTON: Obama has said that he supports his church and loves his pastor, although he doesn't always agree with everything Wright says and does. Obama held a closed door meeting with Jewish leaders in Ohio last weekend and addressed lingering concerns. He reportedly distanced himself from both Farrakhan and Wright.

Despite the controversies, University of Oklahoma political science professor Allen Hertzke believes Obama will do well among religious voters.

Dr. HERTZKE: Barack Obama seems very comfortable in a faith-based milieu. In fact, he prays with his staff before major events, and he campaigns in churches. In some ways, there's a greater challenge for Republicans because of the enmity that some in the religious right have for John McCain.

LAWTON: For his part, Obama continues to make religion a key part of his campaign strategy.

Senator BARACK OBAMA (in speech): Let's come together, Protestant and Catholic, Muslim and Hindu and Jew, believer and, yes, nonbeliever alike. We're not going to agree on everything, but we can disagree without being disagreeable.