Opponents and supporters of same-sex marriage are urging Gallaudet University to reinstate an administrator placed on paid leave after she signed a ballot petition calling for a vote on the issue in Maryland.

By mid-afternoon Friday, more than 15,000 people had signed an online petition calling on the university for the deaf and hard of hearing to reverse itself and bring back Angela McCaskill, its chief diversity officer. The school disciplined McCaskill on Wednesday, saying her signature on a petition for a referendum on same-sex marriage was “inappropriate.”

The petition to reinstate McCaskill was placed prominently on the Web site of the Family Research Council, a conservative lobbying group that opposes same-sex marriage. On the council’s Facebook page, more than 3,000 people “liked” a post demanding that the school “Reinstate Dr. McCaskill.”

“Gallaudet University’s action underscores that far more is at stake in redefining marriage than two people walking down the aisle,” FRC President Tony Perkins said in a statement, adding that if the ballot measure passes, he expects further discrimination against defenders of traditional marriage.

Maryland Gov. Martin O’Malley (D), who supports same-sex marriage, and Marylanders for Marriage Equality have also called for the school to reinstate McCaskill.

“Everyone is entitled to free speech and to their own opinion about Question 6, which is about treating everyone fairly and equally under the law,” said Josh Levin, the campaign manager for the marriage equality group.

The groundswell of support for McCaskill extended to the megachurches in Prince George’s County, where opposition to same-sex marriage is particularly strong.

Lee P. Washington, pastor of Reid Temple AME Church, one of the largest churches in the Washington region and a hub of social and political activity, encouraged Gallaudet to take back McCaskill, who is a member of his church. In a statement, Washington said that McCaskill and her family had withstood “threats and intimidation” related to her signing the ballot petition and being placed on leave.

McCaskill was among more than 200,000 Maryland residents who signed a petition for a referendum on same-sex marriage. The public vote was favored by opponents of a same-sex marriage law that O’Malley signed in March.

Although petitions are available for public viewing, this petition was broadly disseminated after the Washington Blade, a newspaper that serves the gay community, posted it online in the summer, including a list of the names and addresses of people who had signed it and a color-coded map showing “concentrations” of signatories.

Derek McCoy, chairman of the Maryland Marriage Alliance, which supports marriage only between a man and a woman, said friends and relatives of McCaskill’s told him that after her name became public, people approached her and said, “Why did you sign the petition? Why do you hate me?” McCoy characterized it as harassment and bullying.

People who favor limiting marriage to opposite-sex couples are being made to feel like outcasts, McCoy said. That’s why the McCaskill case is striking a nerve.

“She was at Gallaudet for 23 years,” he said. “Every day she was performing her duty with integrity. Then, when they find out she signed a referendum, all of a sudden she’s incapable of doing her job. It’s incredible.”

University officials have been tight-lipped about what they may be considering for McCaskill.

Their only public comment came Wednesday, when Gallaudet President T. Alan Hurwitz said he had placed her on administrative leave because she had “participated in a legislative initiative that some feel is inappropriate for an individual serving as Chief Diversity Officer.” He said he would be mulling over “the appropriate next steps.”

The university declined to be more specific Friday about whether there is a specific policy McCaskill violated or to explain why it was inappropriate for her to sign a ballot petition.

The FRC’s Perkins said in his statement that Hurwitz should be fired.

He compared the university president’s action to mayors who chastised Chick-fil-A after its chief executive spoke out against same-sex marriage, and he predicted that the punishment against McCaskill would have a chilling effect on people voicing some views.

“If this is allowed to stand, others will follow,” he said.

John Wagner contributed to this report.