NEW YORK — Religious freedom laws like the one causing an uproar in Indiana have never been successfully used to defend discrimination against gays — and have rarely been used at all, legal experts say.

However, past may not be prologue in these cases because gays have only recently won widespread legalization of same-sex marriage, and religious conservatives are now scrambling for new legal strategies to blunt the trend.

“There's an inability to look to the past as a reliable predictor of the future on this,” said Robert Tuttle, a church-state expert at George Washington University School of Law. “If what you're saying is that it can be certain it won't be used — you can't know that because this is now a different situation.”

Last week, Indiana Gov. Mike Pence signed the state Religious Freedom Restoration Act, giving heightened protections to businesses and individuals who object on religious grounds to providing certain services. The law triggered a swift and intense backlash from gay rights supporters, businesses such as Apple, and some states, which barred government-funded travel to Indiana.

Critics of the law say the intent is to discriminate against gays. They fear, for example, that caterers, florists, photographers and bakers with religious objections to same-sex marriage will be allowed to refuse to do business with gay couples. Supporters of the law say it will only give religious objectors a chance to bring their case before a judge.

On Tuesday, Pence said he wants the Legislature to present him a bill by the end of the week clarifying the new law does not allow discrimination against gays.

Pence said he does not believe lawmakers intended “to create a license to discriminate.” But he added: “I can appreciate that that's become the perception, not just here in Indiana but all across the country.”

Douglas Laycock, a constitutional scholar at the University of Virginia Law School who helped win passage of the 1993 federal Religious Freedom Restoration Act, said no one has ever successfully used such laws to override nondiscrimination statutes. He expressed frustration that gay rights advocates seem to be ignoring this in their attack on the Indiana law.

“I don't know if they don't know that, or whether they're pandering to their base,” Laycock said.

But Eunice Rho, advocacy and policy counsel for the American Civil Liberties Union, said the landscape shifted as gay marriage became legal in an increasing number of states over the past three years. Rho noted that when Indiana's bill was moving through the Legislature, its supporters rejected amendments that would have limited its potential to allow discrimination.