The island state that helped make gay marriage a national discussion could be the next state to legalize it after more than two decades.

Many credit a Hawaii case that started in 1990 with prompting action in courts, statehouses and Congress, leading to the federal Defense of Marriage Act in 1996 that was eventually struck down this year by the U.S. Supreme Court.

Now, a special session starting Monday could make Hawaii the newest state to formally legalize gay marriage, a move proponents say would finish the job and exemplify the state’s fabled aloha spirit — while granting equality and spurring tourism.

Opponents have taken up many fronts. Some argue that marriage should be between a man and a woman. Others say the matter should go to a vote, not be rushed outside the regular legislative calendar.

For Dr. Allan Wang, a 56-year-old Hawaii doctor, the issue is about being treated fairly.

"It’s unfair that our amazing relationship — which we’ve been together over 33 years — our amazing relationship cannot be acknowledged," Wang said, sitting next to his partner, Tom Humphreys, a longtime molecular biology professor at the University of Hawaii at Manoa.

Wang and Humphreys, 77, married in California in July, one month after entering a civil union in Hawaii and after decades of pressing for gay marriage in the state. Humphreys said they were effectively forced to marry outside Hawaii after he was diagnosed with terminal prostate cancer and told he had only a short time to live.

They married exactly one week after the U.S. Supreme Court struck down the federal Defense of Marriage Act, granting federal benefits to legally married gay couples. Congress had passed the act in 1996 as part of a growing backlash to a case from Hawaii at the time, after a couple tried to apply for a marriage license in 1990.

Differences between civil unions and full-fledged marriage have been a key part of the debate in Hawaii. A lawsuit pending in the 9th U.S. Circuit Court of Appeals argues that gay couples should be allowed to marry and shouldn’t have to settle for civil unions.

In calling the special session that begins Monday, Gov. Neil Abercrombie said passing gay marriage would help resolve the lawsuit and put Hawaii in line with Supreme Court rulings, which don’t apply to couples in civil unions.

On Friday, the attorney general of Massachusetts, Martha Coakley, filed a brief in the appeals case and another case from Nevada involving couples who argue the state’s ban is not constitutional. Attorneys general from 14 other states are listed as co-counsel.

Coakley said in the filing that civil marriage has been strengthened by removing barriers to access.

"Nevada and Hawaii marriage laws deny gay men and lesbians the fundamental right to marry and codify the second-class status — for its own sake — of same-sex couples and their families," the filing said. "Under any standard of constitutional analysis, they cannot survive review."

Lawmakers and followers of Hawaii’s Legislature — which is heavily Democrat — say they’re confident a bill will pass, but not certain.

"It would appear that it’s going to be difficult for us to prevail, but we’re hopeful," said Father Gary Secor, vicar general of the Catholic Diocese of Honolulu. "The history of the church is that we have not tended to always go with popular or prevailing opinion about things."

Rep. Chris Lee, a Kailua Democrat who supports the bill, said legislators have been bombarded by passionate calls on both sides.

Jim Hochberg, president of Hawaii Family Advocates, said coalitions from every Hawaii island are building to push for a public vote.

"They don’t support the concept of same-sex marriage. They don’t support the special session," Hochberg said. "They want to vote on it."

The legislative hearings are expected to draw heavy crowds, with an opposition rally planned Monday night.