Gay rights groups say they are saddened by Hawaii Governor Linda Lingle's Tuesday veto against civil unions for gay couples.

“Today is a sad day for the thousands of Hawaii families who remain second class citizens,” Alan Spector, legislative affairs co-chair for Equality Hawaii, said. The group had lobbied hard for Lingle to approve the bill that would have recognized gay and lesbian couples with civil unions.

The Republican governor rejected the measure approved by lawmakers in April after considering the issue over the entire 45 days allowed by law. She said she vetoed the bill because it was too similar to marriage.

The bill is “essentially same sex marriage by another name,” she said.

Lingle has said she believes marriage is a heterosexual union. But eight years ago, she promised she would sign a bill that grants gay couples similar rights.

“On the issue of domestic partnerships, I have stated that if the Legislature [should] pass legislation granting certain rights, I would not veto that legislation,” Lingle answered PBS moderator Linda Taira during a live debate.

Nationwide gay rights groups have also expressed their disappointment with Lingle's decision.

“Americans nationwide share in the disappointment and outrage of thousands of Hawaii's families who will not receive equal treatment under law,” Joe Solmonese, president of the Human Rights Campaign (HRC), the nation's largest gay advocate, said.

Other groups had harsher words for the governor, including the Rev. Carolyn M. Golojuch, who heads the Oahu chapter of PFLAG, a support group for parents and friends of people who are gay, lesbian, bisexual or transgender.

Golojuch said Lingle's decision had “denied” gay couples “social justice.”

“Her denial is a violation of the integrity of her office and a violation of her oath of office,” she said. “Governor Lingle's denial of equal rights, benefits and protections for one segment of our citizens is a denial for all of our citizens of Hawaii.”

The latest round in Hawaii's long-running gay marriage debate began last year when the bill easily cleared the House but stalled in the state Senate. The bill was amended to include heterosexual couples, but the session ended without a debate. When lawmakers reconvened in January, senators approved the amended version of the measure but House leaders left the bill unattended until the final day of the legislative session in April. Late on that day, House Majority Leader Blake Oshiro made a motion to bring back the measure. Oshiro, an openly gay Democrat, previously denied he would revive the measure.

The last-minute moves were blasted by Lingle in her veto announcement. She called reviving the civil unions bill on the final day of the legislative session “wrong” and “unfair.”

Lingle's decision is expected to be the final say on the debate for now because lawmakers failed to approve the measure with a veto-proof majority.

Still, some gay rights advocates, including Freedom to Marry, a group that lobbies for marriage equality throughout the nation, are calling on the Legislature to override the governor's veto.

House leaders announced Friday they would not attempt to override any of the governor's vetoes.

Hawaii was the first state to grapple with gay marriage when the state Supreme Court struck down a law that limited marriage to heterosexual couples in 1993. But in approving a constitutional amendment that defines marriage as a heterosexual union, voters overturned the decision in 1998. The amendment leaves the door open for other forms of legal recognition for gay and lesbian couples.