Why the Prop 8 ruling scares religious conservatives

''The evidence shows conclusively that moral and religious views form the only basis for a belief that same-sex couples are different from opposite-sex couples," Walker wrote in his sweeping, 136-page decision.

''These interests do not provide a rational basis for supporting Proposition 8."

Religion, in Walker's reasoning, amounts to a "private moral view," which should not infringe upon the constitutional rights of others.

While some legal scholars say Walker's decision lands on firm legal ground — a law must advance a secular purpose to pass constitutional muster — some religious leaders accuse the judge of trying to scrub faith from the public square.

''Judge Walker claimed to read the minds of California's voters, arguing that the majority voted for Proposition 8 based on religious opposition to homosexuality, which he then rejected as an illegitimate state interest," R. Albert Mohler, president of a leading Southern Baptist seminary in Kentucky, wrote in an online column.

''In essence, this establishes secularism as the only acceptable basis for moral judgment on the part of voters," Mohler said.

On Thursday, Prop 8's supporters filed an appeal of Walker's decision. Jim Campbell, an attorney with the Alliance Defense Fund, a conservative Christian law firm involved in the litigation, said the religious freedom argument will play an important role as the case moves up the federal judicial ladder — including, potentially, the Supreme Court.

''At bottom, our strategy here is, and has always been, that in this country we should respect the rights of the people when they do what they have always done: vote based on their religious and moral convictions," Campbell said.

Abolitionists, anti-abortion activists, and civil rights activists have all been motivated by personal faith, Campbell argued. "To be blunt, we felt (Walker's decision) was an all-out attack on religion."

Walker did note, however, that no religion will be forced to perform same-sex weddings.

Howard Friedman, an emeritus law professor at Ohio's University of Toledo, said Walker is not attacking religion per se; he is just not giving religious expression any special consideration.

''He's basically saying that a private moral view isn't a rational basis for legislation," said Friedman, who writes the popular "Religion Clause" blog. "Case law goes both ways on that. There are certainly some cases that say a merely moral view isn't enough to support legislation; on the other hand, there are some cases that talk about laws being a moral view on society."