The California Supreme Court issued a ruling Tuesday upholding Proposition 8, the state's constitutional amendment defining marriage as between a man and a woman.

The court ruled 6-1 that the amendment was not an illegal constitutional revision by the people nor unconstitutional.

According to the ruling, the justices rejected complaints by Proposition 8 challengers "that it is just too easy to amend the California constitution through the initiative process."

"[I]t is not a proper function of this court to curtail that process; we are constitutionally bound to uphold it," the ruling said.

Lauding the decision, Andrew Pugno, general counsel of ProtectMarriage.com, responded, “We are very gratified that the California Supreme Court has upheld Proposition 8. This is the culmination of years of hard work to preserve marriage in California."

Austin R. Nimocks, senior legal counsel for the Alliance Defense Fund, which helped defend Proposition 8 in court hearings, praised the court for respecting the results of fair elections and arriving "at the only correct conclusion: the people of California have a fundamental right to amend their own constitution."

Last November, 52 percent of California voters approved the ballot initiative, which overruled an earlier court decision that had legalized marriage for same-sex couples.

Although same-sex marriage is now banned in the state, the 18,000 gay and lesbian marriages that took place before the November vote have not been invalidated and will continue to be recognized under state law.

Gay rights supporters, however, still denounced the ruling and shouted "shame on you" outside the San Francisco courthouse.

They vowed to continue their fight and take the gay marriage issue back to the voters to repeal Proposition 8.

The Alliance Defense Fund warned that they may see a backlash by "radical activists" as they did when Proposition 8 was approved last year.

"The Alliance Defense Fund and our allies will not be bullied. These attacks will come, but we are prepared."

In the weeks following the November vote, churches and Christians reported acts of vandalism, bullying and some violence from gay rights activists.

According to Pastor Jim Garlow of Skyline Church in San Diego, there were instances of intimidation and bricks being thrown through church windows. Pastors also needed security guards to ensure their protection, he noted.

"I didn't know how violent the radical left was with this issue," Garlow commented earlier to The Christian Post.

Garlow, who rallied the support of thousands last year to help pass Proposition 8, is organizing another rally on Sunday "in support and thanksgiving of natural marriage."