Conservative legal groups lauded the U.S. Supreme Court’s decision to decline an appeal Tuesday from a gay California couple who were denied a license to wed, but warned that pro-family Americans must remain vigilant in the fight to protect marriage as the battle is "far from over."

"This is not just a good day for marriage; it’s a great year for marriage. The case drives another nail in the coffin of same-sex ‘marriage,’" said Matthew Staver, Founder and Chairman of Liberty Counsel.

The Supreme Court refused to intervene in the case "Smelt v. Orange County" without comment, reaffirming the constitutionality of the federal Defense of Marriage Act. Arthur Smelt and Christopher Hammer had sought a marriage license in Southern California’s Orange County in 2004 but were turned down. Soon afterwards, the men filed a lawsuit challenging both the federal DOMA and California laws confining marriage to a union between a man and woman only.

According to the Alliance Defense Fund, the victory is only one piece of a larger battle to define marriage.

"Marriage continues to be under attack because certain special interest groups are trying to reduce it to nothing more than a benefits system for emotionally attached couples," said ADF Senior Counsel Glen Lavy.

Lavy warned Americans to remain vigilant and vocal since many critical decisions are still pending across state courts.

"Americans must continue to remain vigilant in the defense of marriage, especially since the attacks come from numerous directions," he said.