By Tom Watkins, CNN
(CNN) - Same-sex marriage got a boost on two fronts Monday, when the governor of Washington signed a bill legalizing marriage for gay and lesbian couples and the New Jersey state Senate voted 24-16 in favor of a similar bill.
The New Jersey bill now goes to the Assembly, which is slated to vote Thursday. "We're cautiously optimistic" about its chances for passage, said Steven Goldstein, a spokesman for Garden State Equality, which has lobbied for the bill.
But the legislation is threatened in both states.
New Jersey Gov. Chris Christie said last month that the issue "should not be decided by 121 people in the State House in Trenton." Instead, he favors a statewide referendum.
"I think that this is not an issue that should rest solely in my hands, in the hands of the Senate president or in the hands of the speaker or the other 118 members of the Legislature," he said. "Let's let the people of New Jersey decide what is right for the state."
If he vetoes the measure, "the battle for overriding the veto begins," Goldstein said.
Washington state became the latest to sanction same-sex marriage Monday, when Gov. Chris Gregoire signed legislation legalizing it. The law will go into effect in June, when the legislative session ends, but opponents have vowed to try to halt its implementation by putting it on the November ballot.
That possibility did not appear to dampen the spirits of those who attended the bill-signing ceremony.
"We have finally said yes to marriage equality," Gregoire said to applause moments before signing the bill. "It gives same-sex couples the same right to a marriage license as heterosexual couples."
She noted that churches are not required to perform same-sex marriages under the law and expressed confidence that, if put to a state-wide vote, Washingtonians would back the measure.
"I believe our Washingtonians will say yes because it's time for us to stand up for our sons and daughters, our brothers and sisters, our moms and dads, our friends and the couple down the road," she said. "It is time to give our loving gay and lesbian couples the right to a marriage license in Washington state."