(Augusta, Maine) Supporters of Maine’s same-sex marriage law continued Friday to collect far more campaign contributions than their opponents in a referendum that’s being watched nationally.

NO on 1/Protect Maine Equality said in its campaign finance report to the state that it has raised $4 million in its campaign to keep Maine’s same-sex marriage law on the books. That compares to the $2.5 million raised by Stand for Marriage Maine, which forced the people’s veto vote through a petition drive.

Despite the fundraising advantage, NO on 1 was taking nothing for granted, said campaign manager Jesse Connolly.

“We know this is going to be a razor-thin election,” Connolly said.

NO on 1’s report to the Commission on Governmental Ethics and Election Practices showed multiple pages of donations in the $50-$1,000 range, with exceptions from some individuals, including Donald Sussman of Portland at $300,000.

On the other side, the National Organization for Marriage was by far the biggest contributor to Stand for Marriage Maine’s political action committee, with $1.1 million during the latest reporting period. The Roman Catholic Diocese of Portland gave another $152,600.

Throughout the campaign, the Princeton, N.J.-based NOM has donated a total of $1.5 million while the diocese has kicked in $550,000, which includes money from out-of-state dioceses and individual donors.

Stand for Marriage Maine remained at a financial disadvantage to their opponents, but that was no cause for alarm, spokesman Scott Fish said.

“Our hope is that this … will close the gap. We are working hard to get our message out,” said Fish, adding that an intense fundraising push will continue in the days ahead.

George Smith, a State House lobbyist and commentator who has not taken sides on the issue, said a funding advantage like NO on 1’s “almost always guarantees a win.”

But Smith said a problem the repeal opponents still face is that the ballot, which includes two anti-tax questions and one to repeal a state school consolidation law, “is loaded with great issues for conservatives.” Smith believes turnout will be a key element in the off-year vote.

Political action committees were required to file their final campaign contribution reports with the campaign before the end of the day Friday.

Earlier reports showed NO on 1 had raised $2.7 million, compared to $1.1 million for Stand for marriage Maine.

With its Nov. 3 referendum, Maine is seen as a testing ground for gay-marriage laws around the country. Six states recognize gay marriage either by legislative action or court order, while 30 states have constitutionally banned it.