The legal battle over Proposition 8 continues as numerous groups continue filing briefs for and against the California marriage amendment ahead of a state Supreme Court hearing.

The Pacific Justice Institute, a non-profit legal defense organization for religious freedom and civil liberties, filed on Tuesday its second friend-of-the-court brief in support of the measure that California voters passed in November.

In its brief, PJI argues against the claim that Proposition 8, which limits marriage to one man and one woman, unfairly singles out homosexuals. PJI attorneys explain that "reaffirming the limitation of marriage to heterosexual monogamy ... "is not a drastic revision to the state Constitution."

"It is simply inaccurate to say that reaffirming the traditional definition of marriage singles out homosexuals for exclusion," PJI Chief Counsel Kevin Snider, principal author of the brief, stated. "Even the radical re-definition of marriage currently sought by gay activists maintains exclusions based on such factors as age and monogamy. It is hypocritical for them to pretend they are the only group affected by Prop. 8."

PJI President Brad Dacus commented, "In order for marriage to mean anything, it cannot mean everything. The intellectual and moral bankruptcy of the Prop. 8 foes must not be forced on the rest of California."

On the other side of the gay marriage debate, a coalition of more than 50 California labor organizations who represent more than 2 million working men and women also filed an amicus brief on Tuesday in support of the three lawsuits challenging the measure.

"There are fundamental constitutional rights that cannot be abolished by ballot initiative," said Sal Rosselli, president of United Healthcare Workers, in a statement. "Our organizations stand for fairness and equality for working people – not only in the workplace but in all aspects of society. Today we are standing up for all California families in asking the court to overturn Prop 8."

Some religious leaders are also protesting the measure. According to an announcement Tuesday, the California Council of Churches and other religious organizations (including the General Synod of the United Church of Christ, two Episcopal Bishops of California and Los Angeles, and the Progressive Jewish Alliance, among others) will file an amicus brief on Thursday, asking the court to invalidate Proposition 8.

Proposition 8 overruled a May 2008 decision that legalized gay marriage in California. The California Supreme Court agreed last November to review three lawsuits against the amendment. It may hear oral arguments as early as March and a decision could come before June. Meanwhile, the state high court refused to allow same-sex couples to resume marrying before it rules.

The measure has riled gay rights advocates who have marched in numerous protests since the passage.

Labor organization leaders argue in their brief that the amendment would take away a fundamental right and divide citizens into "suspect classifications," meaning it imposes different treatment on groups that are likely the subject of discrimination. They also say the change proposed in the measure is a fundamental change that cannot be made by a simple majority vote.

Liberty Counsel, a non-profit legal organization defending religious freedom and the traditional family, believes otherwise.

The Christian legal group, which is representing the Campaign for California Families, contends that invalidating Proposition 8 would have a devastating effect on the constitutional rights of those who exercised their right to vote on the initiative.

Liberty Counsel announced that it will file a brief in support of Proposition 8 on Thursday.