New Jersey state Senate President Steve Sweeney promised to override Governor Chris Christie's veto of a same-sex marriage bill by January 2014.
The Democrat said the issue does not belong on a referendum ballot, as advocated by the governor, because it's a matter of civil rights.
"How can it not be when I have a certain right and I'm allowed to do something and you're not?" Sweeney said on CNN Sunday. "That's what we fought over and that's what this country's been founded on is fairness."
Sweeney appeared opposite Republican Assembly Minority Leader Jon Bramnick who agrees with the governor.
"It's not a civil rights issue, and you can see that by Democrats and Republicans both having the same view at least some of them on the same side of this issue," Bramnick said.
He framed a referendum as a compromise by the Republican governor. Sweeney argued that when a majority is asked to vote for civil rights for a minority, the results are always unfair.
Christie followed through on his promise to veto the same sex marriage bill last Friday, a day after the state Assembly passed it. The Senate approved it last Monday.