A nonprofit Christian group wants to intervene in Hawaii’s same-sex marriage federal court case and defend state laws codifying marriage as being between a man and a woman.

The move by the Hawaii Family Forum could heat up what promises to be contentious and complicated litigation that already features one quirk: Gov. Neil Abercrombie contends that Hawaii’s same-sex marriage law violates the U.S. Constitution even as his Health Department director plans to uphold the law.

Natasha Jackson and Janin Kleid, who were denied a marriage license by the Health Department, and Gary Bradley, who entered a civil union with a male partner, filed the federal lawsuit in December.

The lawsuit seeks a judgment declaring Hawaii’s prohibition against same-sex marriages a violation of due process and equal protection rights under the U S. Constitution.

It was filed against Abercrombie and Health Director Loretta Fuddy.

The case is still in its early stages, but could lead to legal gymnastics with two sets of lawyers from the Attorney General’s Office separately representing the conflicting interests of the governor and health director.

The first hearing, during which the two sets of lawyers will present their views, is scheduled for April 30, when Senior U.S. District Judge Alan Kay hears HFF’s request to join in the case.

HFF is represented by the Alliance Defense Fund, whose attorneys also defended California’s Proposition 8, which sought to quash same-sex marriages but was struck down by federal courts.

James Hochberg, a Honolulu attorney who also represents HFF, said his client wants to "vigorously defend" the state laws.

"Marriage is not a political plaything as those who demand its redefinition have treated it," he said last week. "HFF and ADF will continue to unapologetically defend marriage as the unique, life-giving foundation that created and sustains our civilization."

John D’Amato, the Hono­lulu lawyer representing the three plaintiffs, said they will strongly oppose the intervention.

D’Amato said the views of HFF and the defense fund show the "hostility" that gays and lesbians face daily. He cited a statement from the fund that says the "homosexual agenda" is attacking "God’s plan for marriage."

"We deny the extreme views of the Hawaii Family Forum and the Alliance Defense Fund represent those of most Christians, let alone of most people in our state," he said.

The lawyers from the Attorney General’s Office are not commenting beyond what’s in their legal papers, office spokesman Josh Wisch said.

The massive and highly publicized California litigation over same-sex marriages has some parallels with Hawaii’s brush with legalizing those marriages, but with one significant difference.

Hawaii’s courts declared the same-sex marriage ban a violation of the state Constitution’s provisions of providing equal protection under the law. But a 1998 state constitutional amendment approved by voters essentially negated those rulings.

HFF was one of the leaders of the campaign urging passage of the amendment. It also campaigned against Hawaii’s civil unions legislation, which Abercrombie signed into law last year.

In California, the Supreme Court also declared the state’s same-sex marriage ban a violation of its constitution, but the voter-approved Proposition 8 overruled those court decisions.

Like Abercrombie, former California Gov. Arnold Schwarzenegger declined to defend Proposition 8 in the courts, which permitted the intervention of groups seeking to keep marriage between opposite-sex couples.

In February, a three-judge panel of the 9th U.S. Circuit Court of Appeals ruled that Proposition 8 violated the U.S. Constitution.

But the majority narrowly tailored the ruling to the circumstances in California, which for a period allowed same-sex marriages before the passage of Proposition 8.

The federal panel’s majority decision essentially struck down the proposition because it took away rights once enjoyed by gays and lesbians.

Hawaii’s gays and lesbians cannot legally get married because the Hawaii courts stayed their rulings pending appeals. Then the constitutional amendment rendered the Hawaii courts’ rulings moot.

In asking to intervene, HFF contends that Abercrombie won’t represent the interest of the group in preserving marriage as between a man and a woman.

Abercrombie joined forces with the same-sex marriage advocates, while Fuddy’s interest in defending the law is "fundamentally different and weaker" than the group’s interest, HFF said in its request.

"If she loses the case, she loses nothing," the group said.

But if the constitutional challenge succeeds, HFF will "lose the fruit of its massive investment of resources and long-term commitment to preserving the measure that it has tirelessly worked to pass and protect."

Abercrombie’s response to the lawsuit bolsters the plaintiffs’ case.

"This is inequality, and I will not defend it," he said in a statement when he filed his response to the suit.

D’Amato, the plaintiffs’ lawyer, applauded the governor’s position as "heroic" and "courageous." But he indicated that he was not willing to exploit it for a quick ruling in his favor.

He said he is not planning to request a dismissal of the suit against Fuddy, leaving only Abercrombie in the case to pave the way for a summary judgment declaring the state marriage law unconstitutional.

D’Amato said he wants to present expert testimony to support his case to establish a factual record to support the judgment. He said he also thinks Kay, the federal district judge, would want a trial on the issues.

"We’re not going to win this by default," D’Amato said.

In addition, if Fuddy is dropped from the case, it would "open the door" for others to intervene, D’Amato said.

D’Amato said he thinks Abercrombie will oppose HFF’s request to intervene, but doesn’t know what position Fuddy will take.

"We intend to make the case against the active state defendant," he said.