"What most trusting Americans fail to grasp is the correlation between the advancement of the homosexual agenda and the gradual erosion of our religious liberty," said Bruce Hausknecht, judicial analyst for Focus on the Family Action.
"California's judicially imposed social experiment in marriage has hastened the demise of religious freedom across the U.S."
Elaine Huguenin, a Christian photographer in New Mexico, has already seen her First Amendment rights set aside, in favor of gay "rights."
Earlier this year, the New Mexico Human Rights Commission found Huguenin guilty of discrimination and fined her company more than $6,600 after she refused to photograph a same-sex "commitment ceremony."
Jordan Lorence, senior counsel for the Alliance Defense Fund, is representing Huguenin and her husband, Jon. He said businesses and charities should not be forced to endorse something they don't believe.
"It's compelled speech," Lorence told NPR. "You're using the arm of the government (to) punish people for disagreeing with you."
Marc Stern, general counsel for the American Jewish Congress, told NPR the outlook is grim for religious groups.
After Massachusetts legalized gay "marriage," a Boston Catholic charity dropped its adoption services, rather than violate its beliefs by placing children with same-sex couples.
In New Jersey, the arrival of civil unions led almost immediately to a church losing part of its tax-exempt status for refusing to allow a lesbian "commitment ceremony" to take place on church property.
"If the ultimate result of gay 'marriage' and other items on the homosexual agenda is that pastors and believers can be prosecuted and silenced," Hausknecht said, "then we have truly lost the religious freedoms that this country was founded upon."