Republicans began pushing for the constitutional change soon after they won back control of both chambers of the state legislature in last year's wipeout elections. Hundreds of demonstrators from both sides flooded the state Capitol as the divisive debate moved forward, culminating in late May when the House voted 70-62 to send the proposed amendment to referendum.
Following the vote, Gov Mark Dayton (D) issued a symbolic veto, saying that the law was, "mean-spirited, un-Minnesotan and un-American." Citing the founding fathers and the 14th Amendment, Dayton wrote that the proposed amendment would "selectively deny" rights to an entire group of people while bestowing them on others.
"In other words, all American citizens are entitled to the same equal rights and protections under the law," Dayton wrote. "That would clearly include the right of a citizen to marry the person he or she loves."
Dayton's veto does not carry any legal weight because as a constitutional amendment, voters get to decide the bill's fate at referendum.
Given how closely voters are split, it's not surprising then that the issue has quickly become hotbed of debate, with activists on both sides already bracing for a protracted -- and undoubtedly expensive -- two-year campaign.
"It is incumbent upon our side to do the work to raise the money necessary, to recruit volunteers, to really put a good ground group in play to counter what I will assure you will be an endless string of lies," Michael Cole-Schwartz, press secretary for Human Rights Campaign told TPM.
"It will be a long and difficult campaign that wil require a lot of energy," he added.
Donors dropped a combined $83 million to both sides in the fiercely fought battle over California's Proposition 8, which narrowly passed in 2009 and has been appealed upward toward the Supreme Court ever since.
However, those hoping to stop Minnesota's ban from going through are taking heart in a couple of new developments indicating that public opinion has shifted dramatically from where it was just two years ago when Prop 8 went through. For one, the Obama administration said earlier this year that parts of the Defense of Marriage Act -- the federal law barring the government from recognizing same sex marriages -- was unconstitutional. In addition, a flurry of recent polls have found that for the first time ever, a majority of Americans support legalizing same sex marriage.
"We're in a very different place as a country than we were just a few years ago," Cole-Schwartz said. "We have a real opportunity with this campaign to change the tide. And at the end of the day we have a lot of confidence that we can win this."