For a "No" vote, Mike Tate, campaign director for Fair Wisconsin.
"Gay marriage is already illegal in Wisconsin and nothing on the ballot can change that," said Tate.
The something that could change it is a decision by the Wisconsin courts saying current law violates the Wisconsin Constitution, similar to what happened in Massachusetts. The proposed amendment would prevent that.
For a "Yes" vote, Julaine Appling, CEO of the Family Research Institute of Wisconsin.
"Vermont-style civil unions are exactly the same as marriage," she continued. "Who gets to define marriage? We, the people, or a judge?"
In Vermont, it was the courts which mandated civil unions. That's why the proposed amendment [2 pp. pdf] has it's second sentence.