The ruling comes as the legal fight has shifted to marriage. More than 500 gay and lesbian couples took advantage of the week last month after a federal judge ruled the ban unconstitutional and before she granted Wisconsin a stay.
Wisconsin voters approved a constitutional ban on same-sex marriage in 2006. Three years later, a Democratic majority in the legislature passed the domestic partner bill, which gives couples rights like hospital visitation and inheritance.
Republican Scott Walker, who replaced Democratic Gov. Jim Doyle in 2011, refused to defend the domestic partner law when it was challenged by Wisconsin Family Action, arguing it created an institution that was similar to marriage. The high court found that the backers of the 2006 amendment did not intend to rule out all rights for gay and lesbian couples.
"The framers of the amendment intended specifically to allow legislation that provided a set of rights and benefits to same-sex couples. We are supported in our conclusion by evidence that voters were repeatedly told by amendment proponents that the amendment simply would not preclude a mechanism for legislative grants of certain rights to same-sex couples," Justice N. Patrick Crooks wrote in Thursday's decision.
County clerks in Milwaukee and in Dane County, which includes Madison, the state capital, said the number of applications for domestic partnerships has dropped significantly with couples waiting to see how the court fight over marriage plays out.