Wisconsin Attorney General John Byron “J.B.” Van Hollen said Friday he would not defend the state's gay-inclusive domestic partnership registry, calling it unconstitutional, the AP reported.

The group Wisconsin Family Action (WFA) and the Christian-based Alliance Defense Fund (ADF) have asked the state Supreme Court to strike down the law, arguing that it is prohibited by the state's constitutional ban on gay marriage approved by voters in 2006. WFA supported the passage of the anti-gay marriage amendment as the Family Research Institute.

Despite being challenged, the law that gives gay and lesbian couples access to 43 rights, most of which center around estate planning and hospital visitation issues, took effect earlier in the month.

Van Hollen, a Republican who is eyeing a 2010 run for governor, said: “My duty is to the people of the state of Wisconsin and the highest expression of their will – the constitution of the state of Wisconsin. When the people have spoken by amending our constitution, I will abide by their command. When policy-makers have ignored their words, I will not.”

Van Hollen's decision means the state will need to hire outside counsel to defend the policy.

The registry made Wisconsin the first state with a constitutional amendment banning marriage and civil unions for gay and lesbian couples to recognize their unions. Governor Jim Doyle, a Democrat, lobbied for the legislation by including the language in his biannual state budget approved by lawmakers.

Doyle, who has bowed out of the 2010 gubernatorial race, has said he is confident the law is legal and believes opponents have been deceptive in their public statements.

“The lawyers have all assured me that this is not marriage, but I think most people agree that its a statement of some basic rights that most people in Wisconsin think should be protected,” Doyle told Wisconsin Radio Network.

“These are people, who by the way, when the Wisconsin constitutional amendment was passed made repeated public statements saying that this would not preclude domestic partnership legislation. So now, apparently, they're singing a different tune.”

Over 400 gay and lesbian couples have registered their relationships since the law went into effect on August 3, according to the Wisconsin Department of Health Services.