In his recent column for Defining Ideas, Clint Bolick, a member of the Arizona State Supreme Court, addresses the central question of modern constitutional jurisprudence: What is the proper way to interpret the Constitution? Bolick, who is also my colleague at the Hoover Institution, casts his lot with the late Justice Antonin Scalia and his many followers who endorse textualism as the one proper method. The argument goes as follows: Textualism—the effort to find the accurate meaning of every word of the relevant provision—helps prevent activist judges from undermining the rule of law by creating new rights under the guise of a “living constitution” on such key issues as abortion, the death penalty, and gay rights, even when there is no basis for such rights in the Constitution or the laws as written.

Bolick’s strict textualist approach is a needed antidote to unduly adventurous constitutional interpretations. But however necessary the careful reading of text is to constitutional deliberation, it is not the full story. Sometimes, the courts must overturn erroneous precedents—and other times, they must, by “necessary implication,” read terms into the Constitution for its prohibitions to make sense. In such cases, the text alone is not a large enough tool-kit to do the job.

Let’s consider an issue that shows both the power and the limits of textualism. The Commerce Clause reads: “Congress shall have power . . . to regulate Commerce with foreign Nations, and among the several States, and with the Indian tribes.” In the 1824 case of Gibbons v. Ogden, Chief Justice John Marshall construed the middle phrase dealing with interstate commerce in harmony with the text’s treatment of commerce with foreign nations and the Indian tribes. His interpretation consciously covered all forms of communication and transportation across state lines, but it also excluded agriculture, manufacturing, and mining, in large measure to ensure, sadly, that slavery was immune to regulation or abolition by Congress.