But in the bedroom communities of Eden Prairie and Minnetonka, billboards promoting right-wing candidates and talk show hosts frequently pop up between car dealerships and golf clubs. A sudden proliferation of rainbow flags has made these neighborhoods into unexpected battlegrounds in the state's marriage fight.

It started with Gwin Pratt, a senior pastor at St. Luke Presbyterian Church, which has a long history of advocating for gay rights. After the Minnesota State Legislature voted to include the amendment on the ballot, the congregation began an outreach plan to to oppose it. Cindy Eyden, a member of St. Luke, suggested buying rainbow flags in bulk and distributing them to anyone in the community who was interested. What she didn't know was that her idea would go viral.

Maureen Henderson, a fellow St. Luke congregant, was quick to follow Eyden's lead. "They were selling these rainbow flags, only $2.50 for this full size, beautiful flag, and I looked at it, and bought a whole bunch of flags." Henderson told herself "I'm going to go home to my neighborhood, and see, in our community, if one by one we can hand them out and then together start to address this issue."

So off Henderson went to her home in Eden Prairie, a suburb of 60,000 filled with white-collar professionals, 94 percent of whom are Caucasian. That afternoon, she started going door to door with flags in hand. She was quickly joined by her neighbor Wendy Ivins. They took the picture-perfect neighborhood by storm, engaging their neighbors in respectful conversations. Soon, more and more rainbow flags began to appear in the sleepy cul de sacs, planted on large lots and hanging from wood porches.

On city blocks it would be easy to spot a growing movement, but in Eden Prairie, you have to drive past one spacious home after another to witness the trend. So Ivins sent an email to a few dozen of her neighbors: "As you may have noticed, there are many rainbow flags flying in front of houses in our neighborhood," she wrote. "We are doing this to show support for our gay neighbors, friends and family members and our pledge to VOTE NO on the constitutional amendment that would ban marriage for same-sex couples." She added, "Flying the rainbow flag is not meant to start a confrontation, but rather to start a conversation. I think we can all learn from each other."

Doug Watsabaugh, a neighbor of Henderson and Ivins, acknowledged that Eden Prairie is an unlikely place for such a movement. "It definitely puts us out there more in different ways than we have in the past," he said. "But when we talk about an amendment to the constitution, it's not a small change. Our opportunity and responsibility to say what we believe is here now. And it won't be forever."

Meanwhile, the opposition is strong. Minnetonka and Eden Prairie are part of Minnesota's 3rd congressional district, one of the most affluent in the state, represented by Republican Erik Paulsen. In 2010, Paulsen voted against the Don't Ask Don't Tell Repeal Act, a bill that was later passed with a bipartisan vote.