Ministers and clergy who refuse to sanction same-sex marriages would be protected under a bill now on its way to Gov. Arnold Schwarzenegger's desk.
Leno says the protection might become necessary if Proposition 8 is overturned. Proposition 8 is California's voter-approved ban on gay marriage ban.
Leno's bill says religious institutions from faiths that object to same-sex unions would not be stripped of their tax-exempt status if their clergy refuse to perform weddings for gay couples.
Right now Prop. 8 is headed to a federal appeals court after a judge struck it down earlier this summer.
Leno found himself defend the measure when it was opposed by Sen. Roy Ashburn, another openly gay senator from Bakersfield. Ashburn objected that the bill defines same-sex marriages as civil relationships, which he says puts them in a lesser class than heterosexual marriages.
On Wednesday, the Senate approved the measure 22-11. Next stop is the governor's desk.