United States v. Lopez can be read as a fairly mundane disagreement over the application of a long-settled test. The Government defended the statute under review in the case, the Gun-Free School Zones Act of 1990, along familiar lines as a permissible regulation of activity affecting interstate and foreign commerce.

In this essay, I do not address the question whether Lopez was an important decision. My concern instead is with the problem that underlies Lopez's particular issue of the scope of the commerce power: Given our commitment to limited national government, in what way is the national legislature actually limited? Or, more exactly, how are we to approach the task of constitutional interpretation so as to give appropriate meaning and effect to our commitment to limited national government? Many Supreme Court decisions, of course, pose this question in one fashion or another, but Lopez particularly invites reflection. The specific issue before the Court - the interpretation of Congress's enumerated powers - is our oldest vehicle for debating the problem of giving meaning to national limitation, and all the opinions in Lopez reflect a serious attempt to wrestle with its implications and resolution. At the same time, the sharp divisions among the Justices in Lopez demonstrate that despite its fundamental character, the problem of how to construe the Constitution so as to limit the national government remains uncertain more than two centuries after its ratification.