The U.S. Supreme Court refused to hear an appeal Monday by an anti-marriage equality group fighting to keep its list of donors secret.

According to Buzzfeed, the court denied a petition by the National Organization for Marriage (NOM) challenging a ruling by U.S. First Circuit Court of Appeals judge ordering the group to reveal the list of contributors to a political action committee that helped it overturn a marriage-equality law in Maine three years ago. The issue is back on the ballot this November.

The organization raised $1.9 million in that campaign. State law requires groups that collect $5,000 or more for the purpose of "influencing elections" to register and reveal donors.

Jonathan Wayne, executive director of the Maine Ethics Commission, told The Associated Press on Monday that the list of donors to NOM's campaign will stay sealed while the commission decides whether the group is covered by the law.

"Today's decision by the Supreme Court is an important development," Wayne said. "But no decision has been reached by the commission regarding the National Organization for Marriage's 2009 activities."

NOM has argued that revealing its contributors opens them up to harassment and violates their First Amendment rights. But Matt McTighe, campaign manager for Mainers United for Marriage, a group supporting same sex marriage, said the list isn't the important part of the issue.

"We just think they should play by the same rules as everyone else and disclose where their money comes from," McTighe said, referring to NOM. "If they're going to pour hundreds of thousands of dollars into the campaign like they did in 2009, the people of Maine should know where that money's coming from."

["LGBT flag. Close up." via Yui on Shutterstock.]