The Maine Supreme Judicial Court will hear arguments this week on a national anti-gay-marriage group’s efforts to keep its donor list confidential. The National Organization for Marriage is appealing a Superior Court judge’s decision refusing to vacate subpoenas issued by the Maine Ethics Commission demanding the names of NOM’s donors in a 2009 gay marriage referendum. Voters that year overturned a law passed by legislators allowing same-sex marriage in Maine. The National Organization for Marriage donated about $1.9 million in the campaign. Maine’s campaign disclosure law requires groups that raise or spend more than $5,000 to influence elections to register and disclose donors. NOM says the identities of its donors are shielded by the First Amendment. Oral arguments before Maine’s high court are scheduled Thursday in Portland.