Given the prominent role religion has played in the presidential race, it’s perhaps fitting that Barack Obama and John McCain will make their first joint appearance of the general election pre-campaign this month in a church.

The two senators have agreed to attend a forum the evening of Aug. 16 at the Saddleback Church south of Los Angeles — the church is so large it has four locations — where each candidate will spend an hour answering questions from the pastor, Rick Warren. The broad subjects, the church says, are compassion and leadership. The participants stress that this will not be a debate; the campaigns flipped a coin, and Obama will go first.

The Democrat’s willingness to meet the Republican in an evangelical church in Orange County, one of the most conservative suburbs in the country, is an indication for some religious voters that Obama is serious about trying to get their support.

Saddleback, though, is something of an ideological compromise. It attracts a more politically diverse congregation than many Sunbelt mega-churches. Warren has achieved mainstream success with his book, “The Purpose Driven Life,” and accolades from liberals for his work combatting AIDS.

Warren’s no liberal — before the 2004 election, he wrote fellow pastors to drum up enthusiasm for fighting abortion rights and same-sex marriage — but his focus has shifted to fighting disease and poverty in the developing world.

Obama has spoken at Saddleback before, at a World AIDS Day event in December 2006. And both he and McCain provided recorded video messages for Saddleback’s annual “Global Summit on AIDS and The Church” last November. Even so, the Democrat’s upcoming appearance is making an impression on evangelicals. “Obama is coming through very clearly as an evangelical Christian to other evangelicals,” says Calvin B. DeWitt, an activist in the evangelical environmentalist movement and a professor at the University of Wisconsin in Madison.

Obama may bolster his standing further, particularly among younger evangelicals, DeWitt predicts, by broadening discussions of faith beyond hot-button social issues such as abortion and gay rights. DeWitt says Obama, a member of the United Church of Christ, has already turned some heads by encouraging faith-based organizations to continue providing social services and by speaking in the campaign as an evangelical preacher would, incorporating biblical references into his speeches. It’s a feat that McCain, who has been describing himself as a Baptist for the past year after a lifetime as an Episcopalian, hasn’t even tried, DeWitt says.

Conservative evangelicals, such as Tony Perkins, the president of the Family Research Council in Washington, don’t dispute the point. Perkins recently wrote to supporters noting that Obama, more than McCain, has used the language of faith in his campaign, which is making a difference with voters. “I’ve been in some very conservative churches where four years ago people were asking me how we were going to get George Bush re-elected. They now ask who they should be voting for: McCain or Obama.”

A June poll by the Pew Research Center for the People & the Press found McCain with a better than 2-to-1 lead over Obama among white evangelicals. But President Bush did even better with that group four years ago against Democratic Sen. John Kerry.

Perkins worries that Warren’s agenda for this month’s forum, which includes issues on which Democrats sometimes have more appeal to evangelicals — AIDS, poverty, human rights and the environment, but not abortion and gay rights — might play right into Obama’s strategy.

For his part, Warren says he hopes the event in two weeks will afford both candidates an opportunity to speak from their hearts, free from the likely political rancor of this fall’s official debates. “The primaries proved that Americans care deeply about the faith, values, character and leadership convictions of candidates as much as they do about the issues,” he says. The August forum will provide “a civil and thoughtful format absent the partisan ‘gotcha’ questions that typically produce heat instead of light.”