California took a giant leap toward becoming the first state to ban conversion therapy outright last week when a bill outlawing the discredited gay “cure” treatment passed the State Senate. Conservatives, though, are threatening to take LGBTQ advocates to court if the legislation becomes law.

Sponsored by Assemblymember Evan Low, AB 2943 would ban conversion therapy (sometimes referred to as “reparative therapy”) on individuals of any age. Currently, state law forbids medical or psychological practitioners from offering such services to minors, but a law passed in 2012 — the first of its kind in the nation — did not apply to LGBTQ adults.

This distinction is critical. Of the 698,000 queer and trans people who are survivors of conversion therapy, UCLA’s The Williams Institute claims half were over the age of 18 at the time of their treatment.

AB 2943 would go further than previous efforts to ban conversion therapy — which is currently legal in just 14 states and D.C. — by licensing orientation change efforts as “fraud.” Conversion therapists would, thus, be liable under California’s consumer protection laws.

Low, who is openly gay, told colleagues in the California Assembly earlier this year the bill represents a “very personal issue to [him].”

“Growing up with so much hate, I, too wanted to find out if I could be changed and if anything could work because of the societal pressures that we have,” said Low, who serves as chair of the California LGBT Legislative Caucus. “There is nothing wrong with me. There is nothing that needs to be changed.”

Fellow out legislator Sen. Scott Wiener claimed this bill recognizes that conversion therapy simply doesn’t work.

“There is absolutely no medical or scientific basis to support the sale of these supposed healthcare or physiological services,” Wiener told state lawmakers when the Senate voted on the legislation earlier last week. “Indeed, ‘conversion therapy’ is nothing short of physiological torture.”

AB 2943 was widely supported by both Houses in the California State Legislature.

After the Assembly passed the legislation in April by a significant 50-18 majority, the Senate followed suit on Thursday with a 25-11 vote. The proverbial ballots were cast along party lines: Every Democrat voted in favor of the legislation, and every Republican voted against it, aside from the three conservatives who abstained.

As AB 2943 heads back to the California Assembly to vote on procedural amendments before the governor weighs in, those partisan divides signal the brewing battle ahead.

Religious conservatives oppose the legislation as an attack on both the First Amendment right to free speech and the rights of parents to decide what is best for their children. Opponents warn that if AB 2943 were passed, even the Bible could face censorship under the bill’s anti-fraud provisions.

On a July 26 panel in Washington, D.C., Jenna Ellis of the James Dobson Family Institute (JDFI) called the proposition “dangerous.”

“Essentially, any book, any counseling, anything that discusses same-sex attraction and is against that or trying to counsel away from that would be under the consumer fraud protection element of California’s law,” said Ellis, who serves as the director of the JDFI’s Public Policy Center.

“They want to take away any effort that a parent has to place that [confused] child in any type of ‘counseling’ or ‘psychotherapy’ to deal with what they’re going through,” claimed her JDFI colleague, Executive Director Tim Clinton.

In addition to the Focus on the Family-affiliated organization, other conservative groups who have come out to oppose AB 2943 include the California Family Council (CFC) and the Alliance Defending Freedom (ADF). The Scottsdale, Ariz-based group is the right-wing law firm behind the Masterpiece Cakeshop case, as well as dozens of anti-trans draft bills around the country.

In a legal analysis, the ADF agrees with other opponents of the bill that AB 2943 “outlaws speech.”

“It says that licensed counseling, religious conferences, book sales, and paid speaking engagements could all potentially face legal penalties for promoting ways to reverse unwanted attractions or for expressing traditional Christian teachings on sexuality,” the organization concludes.

The bill’s supporters, however, have hit back at those claims — saying they are a misreading of AB 2943’s intent.

“This bill does not prohibit the sale of the Bible — that’s an argument that we’ve heard — that’s untrue,” Wiener claimed. “It does not in any way prohibit free speech. It doesn’t prohibit anyone from speaking with a counselor, including a religious counselor regarding their sexual orientation, as long as no money is exchanged, as long as no services are sold.”

Opponents, however, are not convinced and are threatening legal action to prove it.

Dr. Michael Brown, host of the right-wing radio program Line of Fire, penned an op-ed for the anti-LGBTQ American Family Association’s One News Now in which he warned that Christians will be “arrested” and “sued” for standing up for their beliefs. Brown further urged people of faith to engage in civil disobedience until the legislation is struck down in court.

“Great is your reward in heaven!” Brown wrote in a Monday editorial posted to the website. “Our brothers and sisters around the world are being exiled or stoned or burned alive or imprisoned or kidnapped for their faith. Surely we can take a little opposition for our faith here in the States.”

“I believe that, if AB 2943 passes, we will see it overturned,” he added, “either through legal challenges that make it to the Supreme Court or through the voice of the people saying, ‘Enough is enough.’”

The free speech argument is a familiar one, however, in California’s years-long fight to ban conversion therapy. Critics of the 2012 legislation — known as State Bill 1172 — filed a lawsuit the same year which resulted in a temporary injunction by Federal District Judge William Shubb, in which he called upon opponents to prove the law indeed violated the First Amendment.

But months later the 9th Circuit Court of Appeals found the law did not do so — ruling it “regulates conduct,” not speech.

“Senate Bill 1172 [which bans therapeutic efforts to change orientation] regulates conduct,” the Aug. 2013 verdict says. “It bans a form of medical treatment for minors; it does nothing to prevent licensed therapists from discussing the pros and cons of SOCE [sexual orientation change efforts] with their patients.”

“Senate Bill 1172 merely prohibits licensed mental health providers from engaging in SOCE with minors,” the decision reads.

Future courts are likely to find similarities in the case of AB 2943.

Lawmakers have until Aug. 31 to pass the legislation, which is extremely likely to be approved by Democratic Gov. Jerry Brown. It has been backed by groups like the American Academy of Pediatrics, California Medical Association, Consumer Attorneys of California, Equality California, Los Angeles LGBT Center, National Center for Lesbian Rights, and The Trevor Project.