McCain, the Republican nominee-in waiting, and Obama, who is closing in on the Democratic nod, both have been slowed by their respective pastor problems. Whether the controversies will play a role in the months ahead remains unclear, but the two candidates face decisions about how clergy fit into their efforts to reach voters informed by faith.
Clergy who have seen colleagues go from relative obscurity to infamy in the course of a 24-hour news cycle face similar choices in weighing whether to talk about politics and candidates.
"This is the new terrain of religious politics," said David Domke, a University of Washington communications professor and co-author of "The God Strategy: How Religion Became a Political Weapon in America." "Politicians have been getting a pass on this for some time, using support from a minister or pastor for their political advantage and not having to answer for what that pastor has said."
Both candidates have reason to pay attention to the faith factor in their White House bids.
Obama, facing false rumors that he is a Muslim, portrays himself as a committed Christian in campaign literature. Obama and Democratic rival Hillary Rodham Clinton employ religious outreach directors and speak freely about their faith, signaling that Democrats will not cede the religious vote to Republicans.
But Obama has been hamstrung by the rhetoric of his former longtime pastor, the Rev. Jeremiah Wright, whose sermons blaming U.S. policies for the Sept. 11 attacks and calls of "God damn America" for its racism became fixtures on the Internet and cable news networks. Obama ultimately cut himself off from Wright.
McCain has sought to shore up evangelicals skeptical about his stances on issues like stem-cell research and his past run-ins with movement leaders. But two evangelical pastors McCain did win over - John Hagee of Texas and Rod Parsley of Ohio - were tied to statements causing offense to all three monotheistic faiths.
Hagee has been criticized as anti-Catholic, but McCain rejected his endorsement only after a Web site unearthed a sermon Hagee gave portraying Hitler as a tool God used to deliver Jews to the promised land.
McCain disowned Parsley's endorsement after ABC News reported that he had called Islam an "anti-Christ" religion and the Prophet Muhammad "the mouthpiece of a conspiracy of spiritual evil."
"Religion can be so effective in mobilizing voters," said John Green, a senior fellow with the Pew Forum for Religion and Public Life. "It can also be particularly damaging if it turns out to be controversial."
McCain supporters say it's unfair to equate his endorsements with the Obama-Wright saga. Wright, after all, was Obama's pastor for 20 years, while neither Hagee nor Parsley ever were pastors to McCain. Obama would have known about Wright's incendiary remarks if he spent any time in church, critics say.
Obama backers counter that a double-standard is at work if the pastors endorsing McCain aren't scrutinized, given that McCain sought them out and praised them as exemplary leaders.
There are differences, but also striking similarities in what befell the two campaigns.
"Wright attracted controversy over sermons and things he said in the context of his church and his tradition of black liberation theology," Green said. "It's the same thing with Hagee. His comments about Hitler and the Catholic Church are much less problematic in the context of his religious community."
A Jewish rabbi from San Antonio who supports Hagee made a similar point about context, saying Hagee was merely lecturing on a perspective of the Holocaust shared by some Jewish scholars.
Not long ago, hearing a pastor's sermon required a visit to church. But with churches posting video on their Web sites and selling audio CDs, the messages are one step removed from YouTube and the scrutiny of reporters, bloggers and opposition researchers on political campaigns.
Rabbi Eric Yoffie, president of the Union for Reform Judaism, said he was reluctant to weigh in on the Hagee Holocaust controversy because the sermons were nine years old. But as he watched the clips on YouTube and learned that Hagee's church recently distributed the sermons, Yoffie spoke out.
To Yoffie, the episode serves a warning that religious leaders should stick to talking about issues and values when it comes to politics and never endorse candidates.
"(Hagee) threw himself into this controversy he couldn't get out of," he said. "All of a sudden, any comment he made about a values issue was intertwined with the political picture and how it would affect the candidate. It's a good lesson for religious leaders of what to avoid and what happens when you don't."
Pastors may endorse candidates as individuals, but not under the auspices of their congregations.
Phil Burress, president of Citizens for Community Values, an Ohio-based evangelical group, said pastors hold greater influence if they preach to their congregations about where candidates stand on issues.
"Sometimes I think these guys are better off keeping their mouth shut," Burress said. "But they are men of conviction that preach the word of God the way they see it, and if everyone in the evangelical community agreed, we'd have one denomination."
Whether McCain's rejection of Hagee and Parsley will hurt him among evangelicals, Burress said it's hard to say. The evangelical community, after all, is much more diverse than often portrayed, and many evangelicals might disagree with aspects of Hagee and Parsley's theology, he said.
Both political parties' tendency to denounce supporters or fire staff members at the hint of controversy bothers Mark DeMoss, a public relations executive and former executive assistant to Jerry Falwell.
DeMoss volunteered to help Republican Mitt Romney's campaign win evangelical support, and he said he will vote for McCain. But DeMoss said he doesn't think the candidate needed to reject the endorsements.
"When does it stop?" DeMoss said.
"When a pastor becomes a pastor, essentially he becomes a pastor for people who like him and agree with him and subscribe to what he teaches," he said. "When a person becomes a president, he's the president of people who agree with him and don't agree with him. I think the net has to be a little wider."
DeMoss said McCain, already facing an uphill struggle, "may really turn off evangelicals and religious conservatives who think he has just taken political correctness to its extreme."
