In less than a week, we could witness yet another historic event in a year that has been packed with them: the first U.S. state to affirm gay marriage via popular vote.

That state is Maine, whose state legislature passed a law recognizing same-sex marriage this past spring. Opponents launched a petition drive to place a question on the ballot seeking the law’s repeal, and on Nov. 4, Maine voters will trek to the polls to approve or reject the repeal question.

Recognizing the significance of this, same-sex marriage supporters and opponents have poured money into the state to back the two principal groups on each side of the question, Protect Maine Equality (against repeal) and Stand for Marriage Maine (for repeal).

The good news so far: Pro-marriage equality forces have almost twice as much money in their war chest as the opponents do and are running a series of highly effective ads stressing the importance of equal treatment under the law. The bad news: The opponents, led in-state by the Roman Catholic Archdiocese of Portland, are spreading the same message that proved effective in getting California voters to approve Proposition 8, which repealed same-sex marriage in that state.

That message is this: If gay marriage stays legal, they’ll teach your kids about it in school. Even though Maine’s attorney general has publicly said that’s not so, the opponents continue to drill this message into the minds of Maine voters.

Polls throughout the campaign have shown opponents of the repeal leading slightly among Maine voters, but the most recent poll, conducted last week by Public Policy Polling, shows a 48-48 percent tie on the question. As in most other states that have put the issue before the voters, older voters, men, and nonwhites oppose marriage equality, while younger voters, women, and white voters (slightly, in the last case) favor it.

Nate Silver, whose Web site FiveThirtyEight.com provided the most perspicacious reporting on the 2008 Presidential election polls, says it will all come down to who shows up at the polls Nov. 4. There are no other high-profile races to attract Maine voters, and the other questions on the ballot are likely to appeal to conservatives, so making history in Maine means getting those who support equal rights to vote.

Can you do anything to help make this happen? Sure, thanks to the power of the Internet. Your social network probably has some New Englanders on it, and they may in turn know people in Maine. Send this column to them as a reminder that their vote matters. There’s still time to contribute to Protect Maine Equality. And if you’re really motivated to pitch in, you could just head Down East for the weekend and volunteer. We hear that Maine is lovely this time of year, what with the fall foliage and all.

Maine has been a bellwether in years past – the headline for my column comes from an old saying from back when Maine voters reliably voted for the eventual winner in Presidential contests. With luck, it could be a bellwether again, this time for the better.