There will likely be bluster on both sides.
Gay marriage advocates will no doubt chastise Wisconsin Attorney General J.B. Van Hollen for refusing to represent the state in a suit to defend a law instituting the state's new same-sex couple registry. (ADDED: Check.)
On the other hand, opponents of not just gay marriage but also civil unions will assert that of course Van Hollen is right - the Wisconsin Constitution, under an Amendment passed in 2006, prohibits any state recognition of same-sex relationships substantially similar to marriage.
I think Van Hollen's decision is correct, but not necessarily "right."
I think his office's technical legal interpretation of the Wisconsin Constitution is correct. It finds that Chapter 770, which creates a domestic partner legal status, facially violates the language of the 2006 Amendment, which bars a same sex relationship status similar to marriage. It makes sense to refuse to fight for a law that blatantly runs contrary to the express intent of a Constitutional provision, especially when it's possible for the state to appoint replacement counsel in the matter, should the state's Supreme Court take up the matter. Frankly, it's probably a good political move for Van Hollen at the moment.
I think the "second clause" of the 2006 Marriage Amendment - the provision that makes Van Hollen's assertion correct - is wrong, however, and I believe it should be struck from the Constitution via a Constitional Amendment.
It's one thing to ban gay marriage, but it's another thing entirely to bar civil unions between homosexuals wholesale. I can see the argument for semantic resistance to the use of the term "marriage" for a biologically distinct type of relationship, but I have trouble seeing the validity of an argument that bars one consenting adult invidual from entering into a relational contract with one other consenting adult individual, one which has few, if any, harmful effects on third parties.
In the end, substantive rights equality matters more than the labels attached, but I wouldn't be surprised if even the "first clause," the term marriage of the 2006 Marriage Amendment, must be ceded in the legal realm because resistance parallels the defunct "separate but equal" rhetoric about full citizenship quite closely.
I never discussed this distinction fully here - although I discussed the point with a few supporters of the bill on the campaign trail - while I was off the blog in the summer and fall of 2006. It's the reason I ultimately voted against the Constitutional Amendment that November. It's overbroad for the stated purpose of preventing gay marriage at the very least.
Thus, I think Van Hollen is taking the proper approach on domestic partnership legislation under present Wisconsin Constitutional law. But I think that Constitutional provision ought to be changed.