More than 300 Republicans, including Massachusetts Gov. Charlie Baker, are part of a friend of the court brief supporting same-sex marriage as the Supreme Court is reviewing 6th Circuit marriage cases to decide the future of marriage in the United States.
Ken Mehlman, a former Republican National Committee chairman, organized the brief, which was filed late Thursday at the court that will hear oral arguments on April 28, according to Time.
The GOP signatories include Sen. Susan Collins, Sen. Mark Kirk, billionaire David Koch, former New York mayor Rudy Giuliani, former Utah governor Jon Huntsman, retired Gen. Stanley McChrystal and top aides in Mitt Romney's 2012 campaign.
Mehlman, who managed George W. Bush's 2004 re-election campaign, made similar attempts in 2013 prior to the Supreme Court's overturning of California's Proposition 8.
"One of the points that I hope people appreciate when they read the brief is that supporting marriage equality is, in fact, the conservative position," The Boston Globe quotes Mehlman as saying.
Christian groups say the people and their elected representatives, and not unelected judges, should decide if states should legally recognize gay marriage, which is legal in 36 states and the District of Columbia.
Gay rights groups want all 50 states to legalize same-sex marriage.
The Supreme Court announced in January that the justices would consolidate and hear together four cases from Michigan, Ohio, Kentucky and Tennessee.
Central to the case are two questions, whether states are required to license marriages between same-sex couples under the 14th Amendment to the Constitution, which the Michigan case has to decide; and whether the amendment requires states to recognize such marriages when licensed by other states – which the Ohio and Tennessee cases have to decide. The Kentucky case includes both.
"The majority of citizens in each state voted that the law should continue to recognize marriage as the union of a man and a woman," Ryan T. Anderson, a fellow at The Heritage Foundation, said after the announcement.
Anderson pointed out that the 6th Circuit ruled last November that these laws do not violate the U.S. Constitution.
A ruling before the term ends in late June.
Russell Moore, president of the Southern Baptist Convention's Ethics & Religious Liberty Commission, also released a statement at the time, saying this case could potentially transform the cultural landscape of America.
"We should pray for the Court, that they will not seek to redefine marriage," he said. "Marriage was not created by government action, and shouldn't be re-created by government action. Even more than that, we should pray for churches who will know how to articulate and embody a Christian vision of marriage as the one flesh union of a man and a woman in the tumultuous years to come."
Alliance Defending Freedom said the people of every state should remain free to affirm marriage as the union of a man and a woman in their laws.
"Consistent with the Supreme Court's 2013 Windsor decision, which said that 'states have the essential authority to define the marital relation,' the 6th Circuit rightly concluded that the Constitution does not demand that a new view of marriage be judicially imposed on everyone," ADF Senior Counsel Austin R. Nimocks said in a statement at the time. "We are hopeful the Supreme Court will uphold the freedom of the people to affirm marriage."