The U.S. Supreme Court announced on Monday it won’t hear a case brought by the anti-gay National Organization for Marriage challenging a Maine law requiring the organization to reveal its donors.

The high court posted a notice on its website indicating it wouldn’t hear the case, known as National Organization for Marriage v. McKee, without providing comment. The decision means NOM no longer has any avenue of appeal in the case.

NOM, among the most high-profile organizations opposing same-sex marriage, asked the Supreme Court to take the case after the U.S. First Circuit Court of Appeals upheld the constitutionality of the Maine disclosure laws.

In 2009, NOM contributed a total of $1.8 million to Stand for Marriage Maine and was one of the top fundraisers for the political action committee, which funded efforts for a Maine referendum that nullified the same-sex marriage law in the state.

According to Maine law, any organization that makes expenditures of more than $5,000 to influence a ballot question must register and file reports with the Maine Commission on Governmental Ethics & Election Practices.

The anti-gay group contested this law on the basis that NOM shouldn’t be defined as a political action committee and because the statutory scheme of the law was unconstitutionally vague, but the First Circuit denied these arguments. The high court decision on Monday not to take up the case means the appellate court ruling will stand.

NOM didn’t respond to the Washington Blade’s request to comment on the Supreme Court decision or a sense of timing for when they would disclose their donors.

LGBT advocates praised the decision by the Supreme Court and said it’ll keep NOM more transparent in its efforts to stop the advancement of same-sex marriage.

Fred Sainz, the Human Rights Campaign’s vice president of communications, said the Supreme Court’s decision means the court has “once again allowed state disclosure laws to stand.”

“Even conservative judges have rejected NOM’s pleas for secrecy and misguided attempts to thumb its nose at donor disclosure laws,” Sainz said. “At some point, this fringe anti-LGBT group has to realize that it can’t just pick and choose which laws it follows and which laws it ignores.”

Fred Karger, who’s running as an openly gay candidate for the Republican nomination for president, helped bring NOM’s practices to the attention of the Maine Ethics Commission in 2009. He said he’s “thrilled” with the Supreme Court decision.

“They finally will be forced to reveal their donor names,” Karger said. “That is one of my goal in life, to keep them transparent, which is a very tough assignment because that is the opposite approach they take.”

NOM’s has a history of questionable practices with disclosure of its donors. The group has raised more than $284,000 on behalf of Minnesota’s anti-gay marriage amendment, but listed zero donors as the source of the cash. The organization has said that the contributions came from “membership dues,” which allows it to avoid disclosing donors under a loophole in Minnesota law.

However, according to Think Progress, NOM doesn’t have a membership structure by which it can collect dues, at least not publicly, and didn’t list membership dues as a source of revenue in its 2010 tax returns.

Jennifer Pizer, legal director of the Williams Institute at the University of California, Los Angeles, said the Supreme Court decision isn’t surprising because it takes up few petitions and the Maine disclosure law isn’t uncommon.

Pizer said NOM failed to advance their case because it couldn’t substantiate that donors would face threats if their names were public, nor could it successfully make the argument that the Citizens United ruling, which allows for unlimited political contributions from corporations and unions, allows campaign donors to give anonymously.

“It long has been believed that public sunshine on the identities of large donors to campaigns is important for voters assessing both candidates and ballot measures, and that our constitutionally protected rights to participate in the political process are not rights to do so secretly,” Pizer said.

Pizer added future litigation against disclosure laws may occur in the future, but groups like NOM “would want to find different legal theories than the arguments rejected in this case.”

“Today’s ruling probably means that everyone, including NOM, will need to abide by the same campaign finance disclosure rules during the upcoming campaigns as Maine’s voters this fall most likely will be deciding again on marriage for same-sex couples,” Pizer said.

[h/t] SCOTUSblog