He wants to let each state decide….
Check it out:

Wisconsin Gov. Scott Walker (R) is calling for a Constitutional amendment to allow states to define marriage and strip the Supreme Court of its authority over the issue after the justices legalized same-sex marriage nationwide.

“As a result of this decision, the only alternative left for the American people is to support an amendment to the U.S. Constitution to reaffirm the ability of the states to continue to define marriage,” Walker, a likely 2016 contender, said in a statement.