Between the language of Michigan's new constitutional amendment and the language of Kalamazoo's domestic partner benefits, state Attorney General Mike Cox had little choice but to call the city's plan unconstitutional. That leaves the courts as the only recourse to preserve domestic benefits, at least for public employees. The sooner a challenge comes the better, before more difficult precedents get set.

Cox's official opinion carries the force of law unless a court rules otherwise. That means government entities in Michigan cannot offer such benefits in the future, at least using the type of language Kalamazoo used, and benefits written into existing union contracts cannot be renewed.

Cox decided partnership benefits "characterized by reference to the attributes of marriage" fall within the scope of the amendment, which says that "the union of one man and one woman in marriage shall be the only agreement recognized as a marriage or similar union for any purpose." It passed Nov. 2 by a 3-2 margin.

Gov. Jennifer Granholm, the state's previous attorney general, reached a similar conclusion last December, when she suspended domestic partnership benefits in state contracts that were to take effect after the constitutional amendment did. So Cox was hardly forging new ground.

His opinion does seem to leave room to define partnership benefits separately from those offered to married couples, but that would be difficult and open to challenge.

Meanwhile, it's far from clear that Michigan voters intended to deprive public employees of the benefits, especially when, during the campaign, proponents of the gay-marriage ban kept stressing that it was about preserving marriage, not denying benefits.

But the damage is done, making Michigan a less welcoming place and now depriving some families of much needed health insurance. Same-sex partners have almost no legal rights; the opportunity to obtain benefits for their household members, as offered by a few employers, is only a modicum of decency toward loyal employees.

No one need fear that a court challenge will threaten the sanctity of marriage. State law restricted marriage to one woman and one man even before the constitutional amendment. This is about fairness in employment, and equal access to benefits for all working families.