The group trying to defeat the marriage amendment is getting a fresh infusion of cash from the nation's largest gay, lesbian bisexual and transgender civil rights organization.

The Human Rights Campaign is giving Minnesotans United for All Families $250,000 to help defeat a measure that would cement a ban on same-sex marriage in the state's constitution.

"This is a tipping point year in the fight for marriage equality that requires significant investment," said Human Rights Campaign president Chad Griffin. "We are committed to making sure this is the year that our opponents can no longer claim Americans will not support marriage equality at the ballot box."

The contribution is part of a larger, $1 million donation to campaigns in the four states wrestling with same-sex measures this November, including Maryland, Maine and Washington state.

Human Rights Campaign officials said the group plans to contribute more money in Minnesota before the election. The group has given legislative and electoral marriage issues $4.8 million in the last two years. The group already has six staffers in Minnesota working in various roles and will have pumped about $540,000 into the state, after the latest contribution.

"We are grateful for the sign of confidence from all of our national partners and for the Human Right Campaign's commitment to Minnesotans United," said campaign manager Richard Carlbom. "HRC is investing in Minnesota because more than 25,000 Minnesotans have made a personal financial commitment to defeat this hurtful amendment that would limit Minnesotans' freedoms."

Griffin said all four races are winnable and the group wants to ensure the campaigns have enough money.

"They need resources to educate voters and fight back the lies from groups like the National Organization for Marriage," he said. "The country is moving in the direction of equality and a win in any of these states will show that marriage equality is quickly becoming a mainstream, American value."