Minnesota for Marriage, the group promoting a constitutional ban on gay marriage in the state, will debut its first two TV adverts of a heated campaign today.

Both adverts argue that male-female marriage has been a building block of society for centuries.

However, one of the adverts uses the line ‘everyone has a right to love who they choose’ and yet still argues it’s important to keep the traditional definition of marriage between opposite-sex couples only.

With their chief rival campaign, Minnesotans United for All Families having had their ads on TV for the last two weeks, they signal the five-week homestretch for the multimillion-dollar political battle over gay marriage in the US state.

The issue will be voted on 6 November, when the US also goes to the polls to select its next president.

Minnesota for Marriage’s campaign manager, Frank Schubert, told The Associated Press they are spending about $175,000 (â‚¬135,000) to air the two ads throughout October and had asked Catholic households to make donations to continue the airing.

One of the adverts also says: ‘Marriage is more than a commitment between two loving people,’ over images of straight couples getting married, raising children and showing affection.

‘It was made by God, for the creation and care of the next generation,’ it adds.

Minnesotans United for All Families adverts on the other-hand, feature a heterosexual couple discussing how they oppose the ban thanks to a gay couple in their neighborhood that they got to know, whilst another features a man who calls his own marriage the most important thing in his life and says the state’s constitution shouldn’t deny that to anyone.

Minnesotans United campaign manager Richard Carlbom declined to issue specific criticisms on his rivals ads and instead argued against the amendment’s passage.

Carlbom said putting a gay marriage ban in the constitution: ‘Would limit the freedom to marry for some Minnesotans just because of who they are.

‘It permanently singles out and excludes gay and lesbian couples from the love, commitment and responsibility that marriage brings.

‘No-one wants to be told it’s illegal to marry the person you love.’

The two new commercials are the first on TV from gay marriage opponents in any of the four states with the issue on the ballot this fall — Minnesota, Maine, Maryland and Washington.

In previous TV ads produced in California in 2008 and other states, Schubert raised concerns that state-sanctioned gay marriage could expose children to influences and beliefs not approved by their parents.

Neither of the Minnesota adverts resurrect those claims, which outraged gay activists and their allies.

Schubert has made it clear that should the meaning of marriage be redefined, he will create more commercials to emphasise the potential damage it could do.

That could depend on the group’s fundraising in the five weeks to election day in the US.

Schubert said: ‘We’ve poured everything we have into these initial ads and are working hard to raise the funds we need to finish the campaign.’

If the law is passed, the gay marriage amendment would toughen the state’s existing statutory ban on gay marriage by putting it in the constitution.

A Star Tribune poll of 800 likely voters taken in mid-September found a dead heat with the poll’s margin of error, with 49% in support, 47% against and 4% undecided.

Watch the commercials here: