Romney just invoked the old Brandeis quote, which is usually taken to refer to an argument for federalism. Interestingly enough, what Brandeis actually had in mind was scientific socialism.

Modern justices have tended to overlook, or perhaps ignore, the instrumental and ultimately half-hearted nature of Brandeis’s federalist commitment. For example, they have quoted the “laboratory” dictum in the course of celebrating federalism’s virtues of diversity and attentiveness to local circumstances. Brandeis’s view of state experimentation, however, was entirely disconnected from those notions and instead emphasized its value as a step toward federal legislation. . . . Brandeis . . . did not believe in Tenth Amendment or any other constitutional federalism constraints.