HONOLULU -- The ACLU and other pro-civil unions groups expect to file suit in state court within the next month or so, after Gov. Linda Lingle vetoed civil union legislation Tuesday.

They'll ask a judge to rule that Hawaii's state constitution provides equal rights -- including civil unions -- to gay and lesbian couples.

Within a month or so, the ACLU and the gay-rights group Lambda Legal plan to file suit in circuit court, hoping to force the state to allow civil unions.

"We are standing ready to file that lawsuit in short order to ensure that LGBT families in Hawaii are provided equal rights and benefits. To be sure, the Hawaii Constitution already provides that and we're going to make sure that the courts agree with us," said Lois Perrin, legal director of ALCU Hawaii.

"We have a number of plaintiffs that we'll be looking at, who need protection, especially now that the governor has not provided any equal protection for them. These are families and couples," said Loren Javier, western regional director for Lambda Legal. The potential plaintiffs come from across the state, he said.

The lawsuit could take months and possibly years to work its way through the legal system, Perrin said.

Nine states and the District of Columbia offer domestic partnerships, civil unions or same-sex marriages.

In the capitol rotunda, gays, lesbians and their supporters hugged each other Tuesday afternoon following the governor’s veto announcement, some in tears as their defeat sank in.

In a series of speeches, they mocked the governor for saying she wants to put a civil rights issue to a vote of the people.

"We elect representatives to do the job for us. Not to hide behind the people when the job gets tough," said Joann Adams, of the LGBT Democratic Caucus, which advocates for gays, lesbians, bi-sexual and transgender people.

Lingle anticipated that criticism at her veto news conference.

"While ours is a system of representative government, it also is one that recognizes that from time to time there are issues that require the reflection, collective wisdom and consent of the people," Lingle said.

In the minutes after Lingle announced her veto, opponents of the civil union bill cheered outside the governor’s office, and then dropped to their knees, prayed and cried. They also sang a spontaneous round of the hymn “How Great Thou Art” and other religious songs.

"We love our brothers and sisters, whatever walk of life they have. But we're standing on the word of God," said Millie Kane, a member of St. Ann’s Catholic Church in Kaneohe.

Dragos Oprescu, a member of Calvary Chapel Honolulu, said, "Homosexual folks can do whatever they want to but they cannot impose that on the will of Hawaii people to redefine what marriage is."