For weeks, Sen. John McCain's campaign has quietly resisted calls to dump one of his leading religious representatives who critics say is an inappropriate surrogate because of links to allegations of sexual impropriety.

At least three religious groups have asked the McCain campaign to remove Deal W. Hudson from its national Catholic-outreach group. The groups say Hudson, who quit President Bush's political team in 2004 amid similar calls, lacks the moral authority to represent the campaign on religious issues.

Hudson left a tenured professorship at Fordham University in New York after a 1994 incident in which he was accused of having sex with a freshman. He was never charged with a crime.

The controversy could hamper McCain's efforts to win over religious voters, who are wary of his candidacy.

The campaign declined to discuss the matter Wednesday and repeated an earlier statement.

"He's a name on a list, a volunteer. When are we going to start talking about gas prices, jobs and the issues facing Americans? The McCain campaign is all done with the 'gotcha' games," said Tucker Bounds, a McCain spokesman.

But those who are troubled by Hudson's background say he is more than a volunteer. Earlier this month, he was identified on a Catholic radio show as a McCain surrogate, and he also hosted a conference call with the deputy chairman of the Republican National Committee discussing the campaign with Catholic media.

"He just shouldn't be representing Catholics for the campaign. It's offensive," said a member of McCain's steering committee who did not want his name used. Catholics "reject him as a moral arbiter."

For McCain, it is the second time his supporters have upset at least some Catholics, a key voting group. In May, McCain rejected the support of the Rev. John Hagee, a Texas-based tel- evangelist who has made several anti-Catholic and anti-Jewish comments.

Hudson, a self-styled "theocon" who now lives in Fairfax, Va., left Fordham after one of his former students sued him, claiming he plied her with drinks and had sex with her when she was 18 years old. The case was later settled.

Hudson, who was a philosophy professor, declined to comment through a spokesman. In an earlier statement, Hudson said: "My past continues to be a source of shame to me and, unfortunately, my family. I'm not blaming anyone for this. It was my own fault. And while the revelation of my failing was deeply humiliating, it was also an important wake-up call for me. Over the past four years, I've tried to make amends with family, friends and supporters."

In 2000, Hudson served as a leading figure for Bush's efforts in courting Catholic voters. In August 2004, he quit Bush's re-election campaign after the National Catholic Reporter outlined the Fordham incident.

In March, Hudson found a home with the McCain campaign, when he was among a list of about 100 "prominent Catholics" supporting the presumptive Republican nominee.

Hudson is director of Inside Catholic.com, a Web site for faith, culture and politics. He has used that outlet to praise McCain for his opposition to abortion rights and gay marriage and attack Sen. Barack Obama for his support of abortion rights.

"There is no doubt that the dramatic progress made in reducing abortions over the last 30 years - now at their lowest number since 1974 - will be rapidly reversed under a President Obama," Hudson wrote this month. This week, he described Virginia Gov. Tim Kaine, who is widely regarded as a potential Obama running mate, as a "pro-abortion Catholic."

Kaine, who is Catholic and spent a year in a Jesuit mission, has said he is personally opposed to abortion but would not restrict a woman's reproductive rights.

Religion has been a recurring issue in this year's presidential election for other candidates, as well.

Former Arkansas Gov. Mike Huckabee, an ordained Southern Baptist minister, faced questions during his run for the Republican nomination about the role his faith would play. So, too, did former Massachusetts Gov. Mitt Romney, who tried to allay concerns about his Mormon faith during his bid.

For more than a month, Obama, the presumptive Democratic nominee, faced heavy criticism for his initial unwillingness to distance himself from his former pastor, the Rev. Jeremiah Wright Jr., who made remarks seen as racially divisive from his Chicago pulpit. In April, Obama created another stir when he said small-town Americans cling to guns and religion out of bitterness in a deteriorating economy.

And throughout the campaign, Obama has faced untrue suggestions that he is a Muslim.

The same day McCain rejected Hagee, he also rejected the support of the Rev. Rod Parsley, an Ohio preacher who gave an anti-Muslim sermon.

Reach the reporter at ronald.hansen@arizonarepublic.com or 602-444-4493.