Even with religious freedom provisions added, LGBT discrimination laws are unlikely to draw support from Catholic bishops because they could in fact lead to discrimination against religious groups, analysts explained.

The idea of adding religious freedom protections to such laws "might seem to work in principle" but "would be extremely difficult, I think, to make work in practice," said Matthew Franck of the Witherspoon Institute, a research center in Princeton, New Jersey.

The Employment Non-Discrimination Act passed the Senate in 2013. The bill would prohibit employers from hiring or firing people based on their "actual or perceived sexual orientation or gender identity."

By protecting LGBT persons as a special, separate class akin to race, laws like the Employment Non-Discrimination Act (ENDA) could enable anti-discrimination lawsuits against businesses and social service organizations that conscientiously object to performing certain services.

For instance, Franck said, a baker in Colorado refused to bake a cake for a same-sex wedding, citing his Christian beliefs. He was then ordered by the state's civil rights commission to change his policies and undergo anti-discrimination training. Business owners like the baker, Jack Phillips, might have no legal recourse to conscience protections if laws on the books recognize LGBT persons as a separate protected class.   

This would leave room for just a "narrow" religious exemption for churches and houses of worship, and not hospitals, orphanages, or businesses, Franck told CNA.

"I just don't know how you actually write meaningful non-discrimination law and still maintain meaningful religious liberty protection in this area," he said.

"Catholic leaders have at their core a conviction about the inviolable dignity of every human being," noted Dr. Chad Pecknold, a professor of historical and systematic theology at the The Catholic University of America in Washington, D.C.

"Anti-discrimination laws can manifest this same conviction. But they can also be discriminatory," he said, adding that ENDA is an example of one such "discriminatory" law.

"[ENDA] actively discriminates against the Church's understanding of key aspects of human nature – most especially the nature of the family and the education of children," Pecknold stated.

"When the Church is being mandated to teach, in word and deed, something contrary to the perennial teaching of the Church, then all citizens should see that this law is a threat to religious liberty – the liberty on which all our other liberties depend."

Last week, leaders of the Church of Latter Day Saints endorsed anti-discrimination protections for LGBT persons "in such areas as housing, employment and public accommodation in hotels, restaurants and transportation," if such measures were to include religious freedom exemptions for religious communities, families, and business owners.

"With understanding and goodwill, including some give and take, none of these rights guaranteed to people of faith will encroach on the rights of gay men and women who wish to live their lives according to their own rights and principles," Elder Jeffrey R. Holland stated.

But while a balance of ENDA and religious freedom may sound appealing, multiple religious freedom experts said that it is unlikely to be achieved in practice, and efforts in this area would likely backfire, leading to religious groups being forced to violate their beliefs.

This potential for the sabotage of efforts to protect religious liberty could be one reason that leaders like the U.S. Bishops and the Southern Baptist Convention continue to oppose laws like ENDA.

"I know the Mormon leaders are standing strong on marriage. They're supporting conjugal marriage, marriage of one man and one woman, as a principle not only in their church but in public policy," Franck said.

"But they've just made it harder for themselves to maintain that position, and I'm afraid, harder for the rest of us."

Dr. David Crawford, the associate dean for academic affairs at the Pontifical John Paul II Institute for Studies on Marriage and the Family in Washington, D.C., said that the U.S. bishops and Southern Baptists offered a "much fuller, better-rounded" response in opposing ENDA that the Mormon leaders did in offering their proposal.

"What they [the bishops] are objecting to is that it [ENDA] would entrench within society more completely by law a kind of a worldview and an outlook that isn't simply about unjust discrimination but is about legitimizing culturally and socially a whole lifestyle and a way of acting and a way of being that goes way beyond simply recognizing that some people may be attracted to people of the opposite sex and that obviously they need to be treated with respect and with dignity," he explained.

Once this lifestyle is officially recognized, very few citizens could religiously object to performing certain services and be protected by law, he added.

Another concern that critics have raised about ENDA is that it fails to distinguish between unjust discrimination and an employer rightfully considering sexual behavior when making hiring and firing decisions. It also fails to differentiate between same-sex attraction and same-sex conduct, prompting fears over the religious liberty of groups that hold moral teachings against homosexual behavior while respecting homosexual persons.

"We and the Catholic Bishops have stood together against legislation along the lines of ENDA because such legislation would not protect those employers who have conscientious reasons for taking into account sexual behavior in their hiring," said Russell Moore, president of the Ethics and Religious Liberty Commission of the Southern Baptist Convention.

Crawford pointed to the example of a Catholic school run by lay persons who have established a Catholic code of conduct. Under ENDA-type legislation, the school could be forced to hire employees who do not abide by the sexual ethics included in the code of conduct.

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.

Finally, critics charged, bills like ENDA could lead to the nationwide legalization of same-sex "marriage."

Once laws like ENDA are enacted, "same-sex marriage…looks like an irresistible next step," explained Franck.

"The pressure for ENDA will be much stronger if the Supreme Court goes for same-sex marriage this June. If people just sort of concede on issues like ENDA now, we actually make it harder to keep arguing for marriage of one man and one woman."

Ultimately, current religious freedom exemptions in anti-discrimination proposals will fall short of their stated goal, the analysts said.

"These religious liberty carve-outs in this sort of environment just don't last very long," Moore said, adding that they "often have a great deal of devil in the details when the regulatory apparatus starts to work."

"I don't honestly expect people who are pressing for new non-discrimination laws, or anti-discrimination laws concerning sexual orientation and gender identity, I don't expect them to agree to meaningful protections of religious freedom," said Franck.

"The most I expect them to concede is some very narrow protection for religious institutions themselves, the kind of protection that costs them nothing to promise because it is already guaranteed by the Constitution, by the First Amendment of the Constitution."