The D.C. Court of Appeals ruled 5-4 Thursday that the city acted within the law when it refused to allow a minister to place a voter initiative on the ballot seeking to overturn the city’s same-sex marriage law.

The court’s nine judges unanimously agreed with the D.C. Board of Elections & Ethics that a ballot measure to overturn the D.C. Marriage Equality Act, if approved by voters, would constitute discrimination prohibited by the city’s Human Rights Act.

But four of the judges, including Chief Judge Eric Washington, dissented from the majority, saying the law banning ballot measures that would result in discrimination prohibited by the Human Rights Act is invalid because the City Council passed it in violation of the congressionally approved D.C. Home Rule Charter. Associate Judge John Fisher wrote the dissenting opinion.

The majority decision, written by Associate Judge Phyllis Thompson, says the Council acted within the scope of the Home Rule Charter and a subsequent charter amendment, which it says gave the Council sufficient discretion to restrict ballot measures from taking away rights protected under the Human Rights Act.

In issuing its decision, the appeals court upheld an earlier ruling by a D.C. Superior Court judge, who also held that the election board acted within the law in denying Bishop Harry Jackson’s petition to file papers to place the Marriage Equality Act on the ballot as a voter initiative.

Jackson, pastor of a church in Beltsville, Md., recruited several D.C. same-sex marriage opponents to join him as plaintiffs in the case, Jackson v. D.C. Board of Elections & Ethics.

Jackson has said he would appeal the case to the U.S. Supreme Court if his side lost at the appeals court level.

Legal experts have said it’s possible — but unlikely — that the Supreme Court would agree to take the case because it is based on a local issue of whether the D.C. Home Rule Charter and a subsequent amendment to the charter allows ballot measures to be held that would result in discrimination. The case would not be on the issue of same-sex marriage itself or whether the U.S. Constitution requires states to accept same-sex marriage, as other pending lawsuits in state courts have asserted.

“The court’s ruling today is a significant victory for justice, the rule of law and the protection of all D.C. residents against discrimination,” said Human Rights Campaign President Joe Solmonese. “It’s time for the National Organization for Marriage to realize equality is here to stay no matter how much money they want to throw at turning back the clock.”

Solmonese was referring to efforts by the National Organization for Marriage, an anti-gay group, to use its sizable financial resources to support Jackson’s campaign to overturn the D.C. Marriage Equality Act.

Solmonese added, “The D.C. Council made a wise decision decades ago that no initiative should be permitted to strip away any individual’s civil rights. The court unanimously found that the proposed anti-marriage initiative would have the effect of causing discrimination, and in doing so, stood up for the entire D.C. community.”

Rev. Anthony Evans, president of the D.C.-based National Black Church Initiative and one of the plaintiffs who joined Jackson in seeking to overturn the same-sex marriage law through an initiative, said opponents of the law will continue their fight.

“Today the court has told the 500,000 residents of the District of Columbia that we have no right to vote on their own laws,” Evans said in a statement. “This is wrong. We should have a right to vote on issues challenging the fabric of our lives here in D.C. Like I’ve said in the past, we will continue to fight — taking this all the way to the Supreme Court. We will not give up easily.”

In the majority decision, Thompson said the claim by Jackson and those who joined him in challenging the city’s decision to ban a marriage ballot measure rested on the technical question of whether the City Council had the authority to pass implementing legislation to restrict voter initiatives or referenda.

“Appellants’ challenge focuses on the validity of Council legislation that requires the [election] board to refuse to accept any proposed initiative that would authorize, or have the effect of authorizing, discrimination prohibited by the Human Rights Act,” Thompson said in the decision.

“Specifically, appellants contend that, in establishing that requirement, the Council overstepped its authority and acted in contravention of the District of Columbia Charter. Alternatively, appellants contend that the proposed initiative would not authorize or have the effect of authorizing prohibited discrimination.

“We disagree with both contentions, and we therefore affirm the Superior Court’s rulings that the Council acted lawfully in imposing the Human Rights Act safeguard and that the [election] board correctly determined that the safeguard required it to reject the proposed initiative.”

D.C. City Council member Phil Mendelson (D-At Large), who chairs the committee that guided the same-sex marriage law through the Council, called the appeals court decision a major victory for the city and the law’s supporters.

“It’s significant that all of the judges agree that Bishop Jackson’s initiative would be discriminatory,” Mendelson said.

Jackson could not be immediately reached for comment.