Though extensive polling does not yet exist, a May 13 survey by the Star Tribune did not find "widespread support" for a constitutional amendment: 55% of respondents opposed the antigay initiative and 39% approved. But it's unclear how a likely multimillion-dollar campaign waged by both sides of the debate will ultimately sway voters.

Whether such an amendment could survive a court challenge if it were passed is also unknown. Though a federal district judge struck down California's Proposition 8 amendment last year, there are key differences between the two states. For one, California had already allowed gay couples to marry prior to Prop. 8's passage: approximately 18,000 same-sex couples remain married in the state, creating what some marriage equality supporters have dubbed a "crazy quilt" of those who can and cannot get legally married.

Minnesota, which has a statute prohibiting gay marriage, has never allowed gay couples to marry. In 1972, the Minnesota Supreme Court ruled in the case Baker v. Nelson that state law prohibits same-sex marriage (the U.S. Supreme Court later dismissed an appeal in the case "for want of a substantial federal question").