Lawmakers and the governor have made history by legalizing same-sex marriage in Maine. This summer, the state and the rest of the nation will watch the fight to overturn their actions unfold.

Opponents of gay marriage wasted no time in filing the paperwork to launch a people's veto, getting a completed application to the Secretary of State's Office on Thursday. The Rev. Bob Emrich, a founder of the Maine Marriage Alliance, filed the document.

Opponents now need to collect 55,087 signatures by mid-September to put a question on the Nov. 3 ballot asking voters to overturn the law. The mechanics of getting those signatures are fairly simple: Volunteers will spread out across the state and ask people to sign petitions.

The campaign waged by each side to win over voters will be involved and intense. And interest in the battle will be nationwide, with money and influence from national groups expected to pour in on both sides.

Maine will be viewed as an "important battleground," said Edward "Ted" O'Meara, head of Ted O'Meara Communications, a public affairs and communications consulting firm. His firm is not involved in the gay-marriage fight.

"Maine's the fifth state (to approve gay marriage) and the only one where both the Legislature and the governor approved it, and courts weren't involved. I think that makes Maine unique," said O'Meara, who worked on the 2005 campaign to uphold Maine's gay-rights laws and last year's campaign to overturn a beverage tax.

"Proponents want to be able to hold up Maine as an example of a state where this has gone through normal channels through legislation and been upheld," O'Meara said. "The opponents are highly motivated to show Maine's the anomaly. On both sides, there's a lot at stake here."

On Thursday, the National Organization for Marriage announced it would help the Maine Marriage Coalition obtain a people's veto.

"NOM stands foursquare with our colleagues in Maine to give voters the ability to overturn this misguided legislation by referendum," Executive Director Brian Brown said in a written statement. "We will devote staff, volunteers and resources to this battle in Maine.

"Marriage means a man and a woman," Brown said, "and we will work hard to ensure that voters in Maine have the ability to do what voters in every other state where they have had a chance have done, and stand up for marriage as we have always known it."

The group raised more than $3 million in last year's successful Proposition 8 campaign to ban same-sex marriage in California and is now running a $1.5 million nationwide ad campaign designed to recruit 2 million activists to support its cause.

Sarah E. Reece, project director for organizing and training at the Washington, D.C.-headquartered National Gay and Lesbian Task Force Action Fund, said her group has worked with Equality Maine and would continue to do so through the summer.

Equality Maine is the state's largest political advocacy group for gay, bisexual and transgender rights.

To date, the task force's foundation has given $82,000 to Equality Maine to hire its first statewide organizer and recruit and train volunteers to talk with voters. It has helped with training, sent organizers to launch a field program and provided $20,000 in seed money to hire nine field organizers.

Scott Davenport, managing director of the New York-based Freedom to Marry coalition, said his group also has been working with Equality Maine and its partners. He doesn't expect the level of outside interest in Maine to match what was seen last year in California, but said there will be some.

"You're going to see groups, influence and money come from outside of Maine," Davenport said. "This is clearly an issue which is not just about Maine, but is national."

According to the California Secretary of State's Office, the primary group opposing gay marriage spent $39...