One of the arguments against the marriage protection amendment is that the type of judicial activism that redefined marriage in Massachusetts and, for all practical purposes, in Vermont and New Jersey "can't happen" here. At a debate in which I participated on Thursday (the Fourth Street Forum), Sen. Lena Taylor, a bright and pleasant woman, argued - incredibly in my view - that the Wisconsin Supreme Court tends to be conservative. That is flat out wrong. It may have been true before Diane Sykes left for the Seventh Circuit and was replaced by Louis Butler, but it's not true today and one of court's conservatives, Justice Wilcox, is about to retire.
In trying to assess whether gay marriage could be mandated by our Court, it is useful to consider its recent decision in Ferdon v. Patient Compensation Fund, the case in which it struck down limits on awards for pain and suffering in medical malpractice cases. Here's a short constitutional law primer: Guarantees of equal protection in the federal and state constitution cannot be read to forbid all discrimination. The law discriminates all the time, e.g., wealthy people pay higher tax rates than poor people, people under 16 can't get a driver's license, you can't practice law unless you do what is necessary to be admitted to the bar.
The federal courts - and most state courts - have dealt with this by adopting a form of multi-tiered scrutiny. Distinctions based on things that we think should never - or almost never - be the basis for treating people differently, e.g., race, will not be allowed unless they are necessary to serve a compelling interest. In practice, this means that they are almost never permitted.
Most other distinctions are subjected to a less exacting standard - often called rational basis scrutiny - which requires only that a distinction be rationally related to a legitimate interest. In practice, this means that they are almost always permitted. (There is also an intermediate form of scrutiny, but we don't need to get into that.)
Sexual orientation has never qualified for anything more than rational basis scrutiny (at least in theory, there is at least one case that may have provided more in practice). This should mean that most distinctions based on sexual orientation would stand. (On, at least, the federal level, this is complicated by potential application of the "right of privacy," but we needn't deal with that here.)
Ferdon involved the kind of distinction - i.e., that between plaintiffs who could establish damages above the threshold and those who cannot - that normally gets "rational basis" scrutiny and the Court in that case did not disagree.
But it announced that it would apply rational basis scrutiny "with teeth" and proceeded to, essentially, substitute its own judgment for that of the legislature as to whether the damages limit was rational.
If the Court continues to apply this new test, there is - in concept if not in practice - virtually nothing that can't be invalidated on equal protection grounds including a limitation of marriage to one man and one woman. The only thing that really restrains the judiciary is a judge's own reticence.
The claim that "it can't happen here" is flat out wrong and, ironically, is now being made by people who want it to happen here and, if the amendment fails, will go to court on November 8 to try and make it happen.