The group seeking to legalize same-sex marriage in Minnesota is launching a petition drive to nudge legislators to pass the law this year.

In its plea to supporters, Minnesotans United for All Families says: "The momentum is on our side, and grassroots marriage supporters just like you are fired up across Minnesota and already having conversations about why marriage matters -- and why 2013 is the year that we must secure the freedom to marry for all loving and committed couples."

The group is expected to unveil its proposal to legalize same-sex marriage next month.

Opponents are already raising money and organizing to block the effort.

After a multimillion-dollar fight, Minnesota voters in November rejected a proposal that would have added a ban on same-sex marriage to the state Constitution.

Same-sex marriage opponents say the vote was not a mandate to redefine marriage and are already making that case to legislators.

To see the petition, go here.