The Maine legislature in May approved a measure permitting same-sex marriages, and it was signed into law by Gov. John Baldacci, making the state one of five in New England to legalize such unions. But religious groups immediately began a push for a ballot initiative to overturn it and the issue has turned into an intense campaign in which gay-marriage supporters have raised $2.7 million and opponents $1.1 million.

A Public Policy Polling survey conducted in mid-October had both sides tied at 48 percent each.

Democrats favor keeping the law by 65 percent to 29 percent, independents agree by 54 percent to 43 percent and Republicans want to throw it out by 75 percent to 19 percent.