NRO's Robert Costa notes that one of the reasons a new poll shows Mitt Romney within the margin of error with Barack Obama in Minnesota (a state Obama won by 10 points in 2008) is the simultaneous Marriage Protection Amendment:

"...A Star Tribune poll released Sunday shows a dead heat, with Obama at 47 percent and Romney at 44 percent. This shocker elated state Republicans, who have been frustrated for decades. (Democrats have won Minnesota since 1972.) To capitalize on the momentum, the Romney campaign recently spent a small sum on television ads.

Democrats are nervous. For months, their electoral calculus has categorized Minnesota as reliably blue. This week, the Washington Post and ABC News reclassified it from “safely” Democrat to “lean Obama.” To stanch the bleeding, Democrats are spending more, and sending in former president Bill Clinton, who will stump near the Twin Cities.

Obama adviser Jim Messina is pushing back; he told reporters on Monday that the idea Romney could win Minnesota is “wishful thinking.” But Republicans’ rising expectations are grounded in more than poll numbers. As Hot Air’s Ed Morrissey reports, there are “two key referendums on the ballot,” and they are dominating the debate and stoking participation.

One measure would amend the state constitution to require photo identification for voting, and the other would constitutionally define marriage as between a man and a woman. Outside groups on both sides have poured in money. These referendums, more than Republican Kurt Bills’s underfunded challenge to Senator Amy Klobuchar, have Republicans enthused."