Hawaii is on the brink of becoming the 16th state to legalize same-sex marriage, but only after dealing with the contentious issue for more than 20 years — longer than any other state in the country.

The House of Representatives approved same-sex marriage legislation on Friday. The state Senate is expected to adopt the House bill on Tuesday, which would send the measure to Gov. Neil Abercrombie for his signature.

For supporters of same-sex marriage, the wait has been much too long.

They plan to celebrate and drop their federal lawsuit seeking to legalize same-sex marriages.

But opponents want voters to decide the issue and believe the wait hasn’t been long enough. They plan to press a state lawsuit to invalidate the legislation.

Ironically, it will now be opponents who appeal to the courts to overturn marriage laws while supporters hope the courts will uphold them.

Same-sex marriage supporters say they do not know of any court in the country that has taken away same-sex marriage rights.

The new Hawaii law will mean an end to a federal lawsuit before the 9th U.S. Circuit Court of Appeals seeking a court order declaring the ban on same-sex marriage to be a violation of the U.S. Constitution.

"It will moot the case because the law has changed," said John D’Amato, attorney for a lesbian couple who filed the lawsuit in late 2011. "My clients will no longer have the complaint they had before because they will now be permitted to be married."

The court case included the unusual dual positions of Abercrombie agreeing that Hawaii’s same-sex marriage ban is unconstitutional, while his health director, Loretta Fuddy, defended the prohibition.

The controversy over same-sex marriages here, however, will linger in state courts.

In anticipation of a law being enacted, opponents want a state judge to strike down the measure as a violation of a 1998 state constitutional amendment and prohibit the state from issuing same-sex marriage licenses.

The only way to legalize same-sex marriages here, opponents maintain, would be through another constitutional amendment ratified by voters.

Circuit Judge Karl Sakamoto on Thursday declined to issue a restraining order sought by state Rep. Bob McDermott to halt action on the special session’s same-sex marriage legislation. But the judge said once the law is adopted, he’ll consider its constitutionality.

The judge raised questions about how voters who ratified the 1998 amendment knew that it authorized the Legislature to later approve same-sex marriages.

"I definitely viewed that as a very positive response," said Jack Dwyer, lawyer for the Republican representative.

But Steven Levinson, a staunch same-sex marriage advocate and the former Supreme Court associate justice who wrote the landmark 1993 opinion on same-sex marriage, said he thinks there’s a "100 percent certainty" that the judge will turn down the request.

He said he doesn’t know of any court case that negated same-sex marriage rights.

Levinson’s opinion on behalf of a splintered Hawaii Supreme Court cleared the way for Hawaii to be the first state in the country to legalize same-sex marriages, a radical idea at the time.

It produced a backlash nationally, with Congress in 1996 passing the Defense of Marriage Act that prohibited federal benefits from going to same-sex married couples.

In Hawaii, the state Legislature adopted a measure in 1994 reserving marriage between a man and a woman; voters then passed an amendment in 1998 that states, "The Legislature shall have the power to reserve marriage to opposite-sex couples."

At the time, same-sex marriage supporters believed the amendment was the most devastating blow for civil rights in Hawaii since statehood.

More than 30 other states adopted amendments, laws or both to ban same-sex marriage.

But the mood in the country and in the courts began to change as attitudes toward gays and lesbians became more tolerant.

The same-sex marriage issue turned into what supporters said was the nation’s leading civil rights controversy.

Starting with Massachusetts in 2004, states began to legalize same-sex marriages.

Massachusetts and four other states legalized the unions through court rulings. Seven states, including Illinois recently, achieved legalization through legislation and three through popular votes.

In June, the U.S. Supreme Court struck down part of the Defense of Marriage Act to allow for married same-sex couples to receive federal benefits, a decision that prompted calls in Hawaii for the special legislative session on the issue.

Hawaii had already recognized the rights of same-sex couples by adopting a civil unions law that became effective in January last year, providing same-sex couples the same rights and benefits as marriage.

Same-sex marriage advocates now view the 1998 amendment in a different light. They say the amendment allows the state Legislature to negate the 1994 legislation and legalize same-sex marriages without putting what would be a matter of civil rights up for a popular vote.

Advocates maintain that the amendment did not flat-out ban same-sex marriages, but was the result of a compromise to allow state lawmakers to change their minds in the future.

"We think now it’s our salvation," said Jackie Young, a supporter of same-sex marriage and a former state representative.