A diverse group of religious leaders – including some who worked on President Obama's re-election campaign – are asking for a religious exemption to a controversial discrimination rule.

"An executive order that does not include a religious exemption will significantly and substantively hamper the work of some religious organizations that are best equipped to serve in common purpose with the federal government," said a July 1 letter to President Obama from a broad group of 14 public religious figures.

"When the capacity of religious organizations is limited, the common good suffers," they cautioned.

The letter comes after reports that an executive order is being drafted to ban employment discrimination against people who identify as gay or transgender. The proposed executive order would be similar to the Employment Non-Discrimination Act (ENDA), which has stalled in the House of Representatives, although it would only apply to federal contractors.

The U.S. bishops have voiced concern over the proposal, saying that while they welcome efforts to end unjust discrimination, including that against homosexual individuals, they fear that ENDA lacks reasonable exemptions for situations in which it is appropriate to consider sexual inclinations and behavior, such as a school setting or public restrooms.

The bill's failure to differentiate between same-sex attraction and same-sex conduct has also drawn concern over the religious liberty of groups that hold moral teachings against homosexual behavior.

In addition, some critics are worried that the wording of the bill treats "gender" as being divorced from physical sex, and uses the terms "sexual orientation" and "gender identity" to describe both behaviors as well as identities.

In anticipation of the executive order, the 14 religious leaders signed a letter asking the president to create "a robust religious exemption" to the proposed rule.

Signatories included Stephen Bauman and Jenny Yang of World Relief, a humanitarian evangelical organization; Andy Crouch, executive director of Christianity Today; Rick Warren, pastor of Saddleback Church and the preacher who gave the invocation at the president's 2009 inauguration; pastor Joel Hunter, whom the president has called a spiritual mentor; Fr. Larry Snyder, CEO of Catholic Charities USA; and Stephen Schneck, director of the Institute for Policy Research and Catholic Studies at The Catholic University of America.

The letter calls for the administration to respect the "diversity of opinion" in the United States, particularly concerning sexuality. It notes that until several years ago, the president himself "believed you could serve your country" without supporting same-sex "marriage."

Religious organizations can serve their country "in partnership with their government and as welcome members of the American family," the letter affirmed, asking the president to protect the equality of religious groups in their ability to serve.

"A religious exemption in your executive order on LGBT employment rights would allow for this, balancing the government's interest in protecting both LGBT Americans, as well as the religious organizations that seek to serve in accordance with their faith and values," the signatories urged.

Letter organizer Michael Wear, who worked in faith outreach for the Obama White House and for Obama's 2012 re-election campaign, told Molly Ball of The Atlantic that this "is not an antagonistic letter by any means."

He explained that following the Supreme Court's rejection of the administration's contraceptive mandate as it applies to some employers, "the administration does have a decision to make whether they want to recalibrate their approach to some of these issues."

Schneck, who co-chaired Catholics for Obama during the 2012 campaign, told the Washington Post that while he thinks LGBT protection and Catholic teaching "fit together pretty well," from a practical perspective, "it just makes perfect sense for the White House to give the faith-based groups time to work this out."

"It's not that long ago when Obama himself was where these faith-based groups are now," he pointed out.

The White House has declined to offer comment on the letter in press conferences or in responses to news media.