PORTLAND, Maine — An appeals court on Tuesday upheld the state’s campaign disclosure law that requires a national anti-gay marriage group to release its donor list, but the group plans to take the fight to shield the list to the U.S. Supreme Court.

The decision pertains to ballot question committees in Maine and represents a second defeat for the National Organization for Marriage, which previously lost a challenge to the state’s political action committee laws and laws governing independent expenditures and advertising attribution and disclaimers.

The latest appeal focused on part of the law that says groups that raise or spend more than $5,000 to influence elections must register and disclose their donors.

The NOM, which says it was founded in 2007 in response to the “growing need for an organized opposition to same-sex marriage in state legislatures,” donated $1.9 million to a political action committee that helped repeal Maine’s same-sex marriage law. It said it believes that releasing the donor list would stymie free speech.

“We already know that the homosexual lobby has launched a national campaign of harassment and intimidation against supporters of traditional marriage, so there’s a good reason to keep these names confidential,” said Indiana lawyer James Bopp Jr., who’s representing the NOM.

Mary Bonauto, an attorney with Boston-based Gay & Lesbian Advocates & Defenders, said Bopp’s claims are an attempt to divert attention from NOM’s failure to follow Maine disclosure rules.

“Courts have said it’s important for voters to know who the donors are for each side since that information may help them decide how to vote.
Everyone else abides by the disclosure rules and so can NOM,” she said Tuesday in an email statement.

The ruling by the 1st Circuit Court of Appeals in Boston, like its earlier decision, will be appealed to the U.S. Supreme Court, Bopp said.

Even if the Supreme Court rejects the appeal, additional action would be required before the donor list could be released. The Maine Commission on Governmental Ethics and Election Practices must conduct an investigation to determine whether the list must be made public.

The NOM has been involved in campaigns against same-sex marriage in Maine and other states. Maine voters repealed the state’s gay marriage law in 2009.

In neighboring New Hampshire, Republicans who control the legislature are mulling whether to repeal a 2009 law legalizing same-sex marriage. Their state is one of six with such laws, along with Connecticut, Iowa, Massachusetts, New York and Vermont, as well as the capital district of Washington.

Gay-marriage advocates announced this week that they’re seeking another referendum in Maine. On Monday, they turned over dozens of cartons of petitions signed by 105,000 voters, far more than the 57,277 needed to force a referendum. If the petitions are certified by election officials, as expected, then the gay-marriage proposal would go to the Legislature for an up or down vote.

If the Legislature approves the proposal and Republican Gov. Paul LePage signs it, then gay marriage will be legalized. If the Legislature doesn’t approve it or the governor doesn’t sign a bill, as expected, then the question goes to voters and would be placed on the November ballot.