Prominent gay rights group Lambda Legal has announced plans to sue New Jersey after senators killed a gay marriage bill on Thursday.

“The requirement to ensure equality for same-sex couples, established by the New Jersey Supreme Court in its decision in our marriage lawsuit in 2006, has not been met,” Kevin Cathcart, executive director of Lambda Legal, said in a statement.

“There is enormous, heartbreaking evidence that civil unions are not equal to marriage, and we will be going back to the courts in New Jersey to fight for equality. Too many families are at risk. We cannot wait any longer.”

In a 20 to 14 vote Thursday, senators killed a gay marriage bill for this session and most likely for the next four years as Governor-elect Chris Christie, a gay marriage opponent, takes office on January 19.

In Lewis v. Harris, the New Jersey Supreme Court unanimously agreed that it is unconstitutional to deny gay and lesbian couples the rights granted to married heterosexual couples and ordered the Legislature to remedy the situation. Lawmakers responded with a civil unions law.

Gay activists say New Jersey's civil unions law is not equal to marriage.

Lawmakers opposed to granting gay couples the right to marry insist they'll fix the civil unions law.

In related news, the first lawsuit to challenge the federal constitutionality of a voter-approved gay marriage ban begins Monday in California.