PORTLAND — In late December 2011, Marc Solomon was holed up in a room at the University of Southern Maine with a cadre of campaign hands who had spent several years fighting a wave of opposition to same-sex marriage around the country.

The group had spent the past year collecting signatures to put same-sex marriage on the ballot in Maine, message testing and practicing new techniques for a field operation that would emphasize gay couples’ desire to proclaim their love, rather than legal arguments about the benefits and rights of marriage.

Solomon, a veteran of the fight for marriage equality in Massachusetts, by then had become the national campaign director for Freedom to Marry, a leading same-sex marriage advocacy group. He and the other activists had assembled in Portland to decide whether the time was right to put marriage on the ballot in Maine.

It was only two years after Mainers had voted against same-sex marriage in a referendum to repeal a marriage law passed by the Maine Legislature and signed by then-Gov. John Baldacci.

“We’d never gone to the ballot on our own volition,” Solomon wrote in a new memoir, titled “Winning Marriage: The Inside Story of How Same-Sex Couples Took on the Politicians and Pundits — and Won.”

“We had only tried fighting off measures advanced by our opponents. So if we were going to do it, we wanted to make sure we were ready,” he wrote. The group — including Matt McTighe and Amy Mello, who had worked with Solomon in Massachusetts — decided that night to make the leap. Solomon would become a steering committee member of Maine’s same-sex marriage campaign. McTighe and Mello would be two of the group’s leaders.

Less than a year later, Maine became one of the first states — along with Minnesota, Maryland and Washington, which also had marriage on the ballot on Election Day 2012 — to approve same-sex marriage in a popular vote.

Today, 34 states and the District of Columbia have opened marriage up to same-sex marriage. Earlier this month, the U.S. Supreme Court announced it will decide four cases on whether states can ban same-sex marriage.

If the court rules in favor of marriage equality, same-sex couples in all 50 states will be allowed to marry.

On Thursday, Solomon was back at USM, holding a reading and book signing at the Glickman Library.

Solomon, a New York resident, sat down with the BDN for an interview about Maine’s marriage campaigns and the state’s legacy in the fight for same-sex marriage. The following interview has been edited for length and clarity.

What made Maine look like an opportunity in 2012, given that it had just voted against gay marriage in 2009?

“2009 was an off year. We knew turnout would be different in a presidential year, and the difference would help us. Plus, the steering committee in Maine had kept at it. There wasn’t a lot of finger-pointing in Maine after 2009. To the credit of their leaders, they kept at it. They had a good structure, and worked well together.”

“It’s a small state, population-wise. We could really do serious retail politics, which we had by then learned was the most effective way to change hearts and minds — to go to people’s doors and engage them in conversation. We were able to hit more than half the swing voters all over the state. That’s very unique.”

Had that strategy been used in other states before Maine?

“We did some of it in California, after Proposition 8 [which repealed same-sex marriage with a popular vote], as a way to test the techniques of how to engage people in those conversations.”

“We really had a wake-up call in California. We did a really close examination of how we talked about marriage, and we realized that straight people didn’t understand why gay people wanted to marry, as ridiculous as that sounds now. We had talked so much about legal protections and rights and benefits, but that’s not why people get married. People get married out of a deep sense of love, and a commitment.”

Are there lessons in that strategy? Does the marriage campaign in Maine include tactics that other advocates could use?

“There’s a lot. Of course every movement is different, but talking about your cause in the context of American values is really important. No. 2 is having a real focus on real people and conversation — face to face, if you can, in a place like Maine, and in bigger states over the airways.”

That sounds very traditional, actually — knocking on doors, talking with voters, trying to change minds. It’s very back-to-basics.

“In a way it is. It’s a very heavy focus on field work, on personal engagement. But it’s also having an active electoral strategy. Making sure you back your friends and try to make examples out of some of your opponents.”

“In Massachusetts, we had every force in the world come out against us — not just the Catholic hierarchy and the Republican Party, the president and the governor, who at that time was Mitt Romney. John Kerry was against marriage, and that was the dominant position of the mainstream Democratic Party. It’s a truism of politics, but for the vast majority of elected officials, the most important thing is keep being elected. If they think they’ll lose their seat, they won’t vote with you.”

[Over two election cycles during his time with MassEquality, Solomon successfully helped nearly 200 lawmakers who voted for marriage equality retain their seats in the Massachusetts Legislature.]

There are still 14 states where same-sex couples can’t marry. What’s next for the movement?

“Hopefully marriage will be legal in Alabama in the next few days. [A U.S. District Court judge recently ruled that Alabama’s ban on same-sex marriage is unconstitutional, but stayed its ruling until Feb. 9 to give the state time to appeal the ruling]. But for now, we’re really focused on winning the ballot of nine justices at the Supreme Court. That’s the approach now.”

What is Maine’s legacy in the marriage fight? When you look back in 50 years, what’s Maine’s part of this story?

“I always tell people that one of the turning points was finally winning the ballot. The elections in 2012 were crucial. We went four out of four at the ballot that year [Maine, Minnesota, Maryland and Washington], and re-elected a president who had come out in full support of marriage equality.”

“With something like marriage, in order to get national resolution, we believed we needed to get critical mass of states and of public support — we knew we had to win at the ballot, even if we don’t think that’s how we should have to win these fights. Then it was real. It wasn’t this abstract idea that our opponents could scare the crap out of people with. It was just regular folks getting married.”