WASHINGTON — More than 30 U.S. religious leaders, including four Catholic bishops, have joined together to call on their country to preserve the “unique meaning of marriage” and to renew respect for religious freedom.

“For many people, accepting a redefinition of marriage would be to act against their consciences and to deny their religious beliefs and moral convictions,” the April 23 open letter said. “No person or community, including religious organizations and individuals of faith, should be forced to accept this redefinition.”

A legal redefinition of marriage would have “serious consequences, especially for religious freedom,” the religious leaders warned. Such a change would affect every law involving marital status and require other relationships to be treated “as if they were the same as the marital relationship of a man and a woman.”

The letter emphasized the need for government protection for those with different views of marriage so that these people may “express their beliefs and convictions without fear of intimidation, marginalization or unwarranted charges that their values imply hostility, animosity or hatred of others.”

The letter was signed by 35 religious leaders from Catholic, Protestant, Orthodox Christian, Mormon and Islamic associations and churches.

The letter, titled “The Defense of Marriage and the Right of Religious Freedom: Reaffirming a Shared Witness,” comes ahead of oral arguments at the U.S. Supreme Court in a case that could rule whether states must grant same-sex “marriage” licenses and recognize same-sex “marriages” contracted in other states.

The recognition of same-sex civil partnerships and of same-sex “marriage,” especially when combined with strict anti-discrimination laws, have caused legal conflicts for religious individuals and organizations.

Some religious adoption agencies have shut down because they would only place children in homes with a mother and a father, and so they could not comply with laws requiring them to place children with same-sex couples. Individuals involved in the wedding industry, such as photographers and cake makers, have faced lawsuits for declining to serve a same-sex ceremony on religious grounds. Some state officials, like judges, also face professional penalties if they act on moral reservations about witnessing same-sex legal unions.

Archbishop Joseph Kurtz of Louisville, Ky., president of the U.S. Conference of Catholic Bishops, signed the April 23 open letter.

“We hope this letter serves as an encouragement to all of us, especially those dedicated to public service, to continue to promote both marriage and religious freedom as integral to a healthy and free society,” Archbishop Kurtz said April 23, according to the bishops’ conference.

He said that marriage as a union of one man and one woman “provides the best context for the birth and rearing of children and should be specially protected by law.”

“Society should work to strengthen the unique bond between husband and wife, knowing that strong marriages build stronger communities,” he said.

The religious leaders’ open letter said that marriage is “the foundation of the family, where children are raised by a mother and a father together.”

The state has a “compelling interest” in maintaining marriage “because it has a compelling interest in the well-being of children,” they said. Marriage safeguards the connection between children and their mother and father and helps provide children the opportunity to be raised “in a stable, loving home,” the letter continued.

The signatories voiced love and respect for “all those who disagree with us.”

Other Catholic signers included Archbishop Salvatore Cordileone of San Francisco, who chairs the U.S. bishops’ Subcommittee for the Promotion and Defense of Marriage; Archbishop William Lori, who heads the bishops’ Ad Hoc Committee on Religious Liberty; and Bishop Richard Malone of Buffalo, N.Y., who heads the bishops’ Committee on Laity, Marriage, Family Life and Youth.

The latest open letter follows up on a Dec. 6, 2010, letter on the protection of marriage and a Jan. 12, 2012, letter on marriage and religious freedom.