Gay couples who have been waging a legal battle for the right to marry in New York State for more than two years will get a final hearing at the state’s highest court tomorrow.

The Court of Appeals is scheduled to hear four cases involving same-sex marriage at 2 p.m. in Albany. The court is planning to broadcast the hearing live over the Internet because of the intense interest, and supporters are expected to gather tonight at churches across the state and a Manhattan synagogue, B’nai Jeshurun on the Upper West Side, for one final public showing.

The cases have been wending through lower courts in the state since 2004, when dozens of gay couples were denied marriage licenses at the city clerk’s office in Lower Manhattan.

The issue has sparked protests from both gay marriage proponents and opponents statewide. It has also dogged Mayor Bloomberg and Attorney General Eliot Spitzer. Messrs. Bloomberg and Spitzer both say they support gay marriage, but their lawyers are leading the fight against it in court.

The final say in the state will now boil down to two hours and 20 minutes at the Albany courthouse.

The senior attorney for the Lambda Legal Defense and Education Fund, the firm representing five gay couples who sued the city after being denied marriage licenses, said yesterday that she has spent the last few days in moot court practice sessions preparing for her 30 minutes in front of the panel of judges.

“We have kind of had our sights set on this day for the last two years,” the attorney, Susan Sommers, a Yale Law School graduate, said during a phone interview. “We’re glad to be closer to the day when hopefully they’ll be able to marry.”

Ms. Sommers – 44, a self-described heterosexual married mother of three – is expected to argue that current law, which prohibits same-sex marriage, is violates the state constitution’s guarantees of due process and equal protection. Briefs already filed by Lambda have characterized the city’s refusal to wed the couples as blatantly discriminatory and detailed personal facts about each couple, including how many children they have and what their children call them (“Dad” and “Pop” in one case).

The city and state – represented by the Bloomberg administration and Mr. Spitzer, the Democratic front-runner in the race for governor – will argue that state law currently defines marriage as a union between a man and woman. Messrs. Bloomberg and Spitzer both say they will support changing the law if the court sides with them.

“The city cannot go and issue licenses when this is all up in the air,” Mr. Bloomberg told reporters before marching in a Memorial Day parade in Queens yesterday.

“If the courts decide that gay marriage is permitted, as the chief of the city, I will direct our city clerk to issue licenses,” Mr. Bloomberg said. He said that even if that happens, he will stick to his pledge of not personally officiating at marriages of anyone other than former mayors and his own children.

The five same-sex couples at the center of the suit against the city won a victory in February 2005 when a state Supreme Court judge, Doris Ling-Cohan, ruled that banning their marriages violated the state constitution. That decision was appealed by the city and struck down by the Supreme Court’s Appellate Division before the Court of Appeals agreed to hear it.

Many of those following the case view the final stop at the Court of Appeals a monumental occasion, but believe that Albany lawmakers will end up taking the matter on whatever the verdict. To date 19 states have passed anti-gay marriage amendments. Massachusetts is the only state that has ruled in favor of gay marriage, while several states, most notably Vermont, have legal civil unions, a step short of marriage.

Those who follow the Court of Appeals have attempted to handicap the outcome, but say it is too tough to call, particularly because earlier this month, one of the seven Justices, Judge Albert Rosenblatt, recused himself from the case. He hasn’t announced why. The state has not made it clear what will happen if there is a three-three tie. It could call up a lower court judge to break the tie or let the status quo, in which gay marriages are not conducted, stand.

A professor at Albany Law School, Vincent Bonventre, said same-sex marriage advocates were counting on Mr. Rosenblatt, who was appointed by Governor Pataki, as a swing vote. Mr. Bonventre, a proponent of gay marriage, said the court is “a very cautious court and it’s fairly conservative,” but that it was one of better courts in the country and could go either way.

Of the six judges other than Mr. Rosenblatt, three were appointed by Governor Cuomo, a Democrat, and three were appointed by Mr. Pataki, who is a Republican and who has said he opposes same-sex marriage.

“Courts are generally reluctant to order considerable social change by judicial fiat,” Mr. Bonventre said. “In addition to that this is not one of the bolder more progressive court of appeals we’ve had … It’s a much different court that it was in the 80s and early 90s.”

The lead attorney on the case for the city of New York is Leonard Koerner, a 1967 graduate of New York University Law School. Mr. Koerner has argued several other high-profile cases for the city, including one over the “Sensation” art exhibit at the Brooklyn Museum. The city’s chief lawyer, Michael Cardozo, whose title is corporation counsel, is not expected to attend the hearing. The American Civil Liberties Union and several private lawyers are representing plaintiffs from other parts of the state.

The lawyer arguing the case for Mr. Spitzer, Peter Schiff, could not be reached yesterday, and e-mails and calls to Mr. Spitzer’s office were not returned on the Memorial Day holiday. Mr. Spitzer recently filed a friend-of-the-court brief in another case on Long Island, saying the state should view a gay union from Vermont as valid in New York. He has publicly defended himself, saying the positions are not inconsistent

The chairman of the state’s Conservative Party, Michael Long, said a decision in favor of gay marriage would amount to nothing more than activism on the bench. The party filed a friend-of-the-court brief on the defense side several weeks ago.

“I certainly hope that the court honors traditional marriage, marriage between a man and a woman. If not they will certainly be setting into motion judicial activism. Those laws if ever changed have to be changed by the legislature,” Mr. Long said.

A civil rights attorney, Norman Siegel, who was representing several same-sex couples in Rockland County in a case that never advanced out of the lower court, said there is a “good chance that our side could get three judges.” Still, he criticized both Messrs. Bloomberg and Spitzer for saying they support gay marriage while opposing the same-sex couples in court.

“How do you reconcile A and B?” Mr. Siegel said. “How are you saying one thing and doing another?”

A spokesman for the Empire State Pride Agenda, Joe Tarver, said the organization has doubled its staff in the last few years in preparation for the case. It has also hired the polling firm Global Strategies, and said that a survey taken in March showed 53% of New Yorkers support gay marriage, up from 47% two years earlier.

The organization, the largest gay lobby in the state, is holding a news conference immediately after the hearing in Albany tomorrow.

The arguments will be available on the Web at www.courts.state.ny.us/ctapps/.