Eugene Volokh on the New Jersey Supreme Court decision on gay marriage:
….this decision, whether you like it or not, seems to be an illustration that the slippery slope is a real phenomenon. Even when there are conceptually quite clear distinctions that could be used to distinguish the first step A from the final step B, A may nonetheless help bring B about.
One can condemn this slippery-slope effect, or praise it. (I support same-sex marriages and civil unions as a policy matter (see PDF page 37), but I don't think that state courts should mandate them as a constitutional matter.) But I think that one can't dismiss the possibility that slippery slope effects, good or bad, are indeed present here, and can be present in similar contexts. And this is so even when, as a purely logical matter, the initial steps (employment discrimination bans, domestic partnership laws, hate crimes laws, and the like) are eminently distinguishable from the final step (same-sex civil unions).
This is an important point to remember folks. This really exists.
UPDATE: Tigerhawk has some excellent points on this. This is the wrong way to accomplish social engineering and in the long run is a setback for proponents of gay marriage. Greg Tinti also has thoughts. This wraps the whole thing up perfectly:
This statement is applicable to many issues championed by the Democratic Party. Too often, too much time is spent trying to figure out how to do something rather than trying to convince people why something is right.