For the third time in less than a year, the D.C. Board of Elections & Ethics has ruled that a ballot measure seeking to ban same-sex marriage cannot be held because it would violate the city’s Human Rights Act.

The board’s ruling Thursday came eight days after opponents and supporters of a gay marriage referendum presented their views on the issue before an expedited public hearing called by the board.

“Based upon the written and oral opinions submitted to the board regarding the propriety of a referendum, as well as its own research and consideration of the matter, the board now concludes that the referendum does not present a proper subject for a referendum because it would authorize discrimination prohibited under the Human Rights Act,” says the ruling.

On two prior occasions, the board and Superior Court judges reached the same conclusion: that a referendum as well as a voter initiative seeking to ban same-sex marriage would violate the city’s human rights law and could not be held.

Similar to the two prior cases, Bishop Harry Jackson, pastor of a Beltsville, Md., church and the lead opponent of same-sex marriage in the District, along with several of his supporters, have vowed to appeal the board’s ruling to the Superior Court.

In an action that could disappoint LGBT activists, the board additionally ruled that the proposed referendum would not violate a separate D.C. election law restriction by interfering with the appropriation of funds or the city budget.

An attorney representing the Gertrude Stein Democratic Club joined the City Council’s attorney in arguing that a ban on same-sex marriage would result in a reduction of as much $1 million in tax revenue generated each year by same-sex weddings. The two attorneys cited a study conducted by the city’s chief financial officer showing that same-sex weddings would be expected to generate significant revenue for D.C. businesses as well as tax revenue for the city.

“[N]otwithstanding the arguments that the [same-sex marriage law] will result in increased revenue for the District, such prospective fiscal impact is insufficient to transform the [law] into an act appropriating funds for the general operation budget,” the board says in its ruling.

It says that various court cases cited by the two attorneys to support the budget argument do not apply in the case of the marriage referendum proposed by Jackson and his backers.

The board’s rejection of the budget argument against a referendum could result in problems for same-sex marriage equality advocates if an appeals court were to side with Jackson and reject the Human Rights Act restriction. Some LGBT activists had hoped the budget argument could be used as a backup plan in the event the human rights law argument runs into trouble at the appeals court level.

The referendum proposal rejected Thursday by the election board calls for overturning the Religious Freedom & Civil Marriage Equality Act of 2009, which the D.C. City Council passed and Mayor Adrian Fenty signed in December. The act would allow same-sex marriages to be performed in the District. It also would authorize churches and religious institutions to refuse to perform such marriages or allow their facilities to be used for such marriages if same-sex unions are contrary to their religious doctrine.

Under the city’s election law, various logistical requirements for a referendum, including the gathering of petition signatures for ballot placement, must be completed before Congress concludes its review of a city law. The congressional review for the marriage bill is expected to be completed March 2, making it unlikely that Jackson and his backers could gather the required petition signatures in time, even if the Superior Court were to rule in their favor.

Last year, Jackson asked the court to extend the deadline for gathering the pettion signature if the court would have ruled to allow a ballot measure to be held. The court rejected that request at the time it rule against the referendum itself.

“I am pleased that the Board of Elections & Ethics has again upheld the Human Rights Act and said that under that a ballot measure to restrict the rights of a minority is not appropriate or allowable under D.C. law,” said Peter Rosenstein, a D.C. gay activist.

Jackson and others calling for the referendum couldn’t immediately be reached for comment.