The Constitution is a charter that has four primary functions. First, it establishes a federal government and defines its powers. Second, it creates within the federal government three branches and defines the legal relations among those branches. Third, it defines certain rights that individuals have against the federal and state governments. Finally, it defines the legal relations that exist among individual states.

Indeed, entire bodies of constitutional law have arisen that are not based on any specific provision. Such law may be based on the nature of the Constitution as a whole or on several provisions taken together. An example of the former is the doctrine of separation of powers. The Constitution does not anywhere use that term, yet the Supreme Court has decided that certain limitations on the power of each branch of government are implicit in the Constitutional scheme. An example of a constitutional doctrine based on several provisions taken together is the right of privacy. The Constitution does not mention a right of privacy, but the Supreme Court has decided that it is created by “emanations” from several of the articles in the Bill of Rights.² In other words, like the separation of powers doctrine, the right of privacy is implied.

Constitutional interpretation is a weightier matter than statutory interpretation. One reason for this is that constitutional provisions, as fundamental law, are intended to be more enduring than statutes and are generally difficult to amend. If a court misconstrues a statute, the legislature can amend the statute with relative ease to make clear the intended meaning. If the court errs in constitutional interpretation, however, the error cannot easily be corrected by an amendment.

Another reason that the ramifications of constitutional interpretation are usually much greater than the ramifications of statutory interpretation is that the Constitution is the supreme law of the land. An interpretation of the Constitution may invalidate laws ranging from federal statutes through local ordinances, whereas the effect of a statutory interpretation is usually far less sweeping.

The differences between constitutional and statutory interpretation have given rise to a rule of judicial restraint whereby the courts seek to decide cases without applying constitutional law, if possible. Assume, for example, that a criminal statute prohibits the sale of “pornography.” A person charged with violation of the statute has at least two arguments: the statute does not apply because the item sold by that person was not pornography as defined by the statute, and even if it applies, the statute is invalid as applied to that person because it violates that person’s constitutional right of free speech. If the court determines that the material is not pornographic, that decision requires that the charges be dismissed, regardless of whether the statute is constitutional or not. Thus, the court will usually consider the issue of statutory interpretation before reaching the issue of constitutional interpretation, because that approach may avoid the need to interpret the Constitution at all.

The tension between an interpretation based on text and one based on extrinsic evidence that pervades statutory interpretation³ is reflected in constitutional interpretation as well. In interpreting the Constitution, courts employ a variety of interpretive theories, including textualism, the theory that questions of constitutional law should be decided by reference to the language of the Constitution, and intentionalism, the theory that questions of constitutional law should be decided by discerning the intent of the framers as expressed in sources outside the text. Textualism and intentionalism are sometimes referred to collectively as originalism because they ultimately look to the original understanding of the framers.

A third alternative, often called nonoriginalism, attempts to interpret the Constitution according to some evolving set of community norms. This third approach is similar to intentionalism in that guidance is sought outside the text, but it differs from intentionalism in that the policies that it seeks to further are not those in the minds of the drafters but those of the contemporary community.

This nonoriginalist approach avoids the obvious limitations of the other approaches. It recognizes that the text of the Constitution is usually too vague to settle most disputes. At the same time, the attempt to discern the intent behind the language is doomed to failure because to fathom the minds of men dead for nearly two hundred years is often not possible, and, in any event, the framers would have had no intent with respect to many issues that arise in the modern world. Indeed, all of the problems that characterize intentionalist theories of statutory interpretation apply with equal or greater force to intentionalist theories of constitutional interpretation. A nonoriginalist theory of interpretation permits a static document to evolve with the times, giving new meaning to terms in response to changing historical circumstances. Many argue that this flexible approach is especially appropriate for a Constitution, which is meant to endure over a period of centuries and thus must be adapted to new situations. Indeed, some argue, the framers of the Constitution themselves believed that the Constitution should be interpreted in this way.

At the same time, nonoriginalism is subject to the criticism that it allows the court to rewrite the Constitution in accordance with its own views, under the pretext that these views represent community sentiment—a criticism that mirrors objections to nonoriginalist theories of statutory interpretation as well. Further, even if the court’s interpretation of community sentiment is accurate, one purpose of the Constitution is to provide a stable set of legal principles that withstand shifts in political sentiment. If the court looks beyond community sentiment to interpret the language of the Constitution, critics of nonoriginalism argue, then the court may become little more than an unelected tyrant, imposing law on the basis of its own whims. Thus, nonoriginalist theories of interpretation are politically controversial, although many scholars argue that no other form of interpretation is truly possible.

The distribution of powers between the federal and state governments reflects the theory of federalism. This section provides a basic description of that theory and illustrates how the Constitution empowers the federal government by discussing briefly one of those empowering clauses, the commerce clause.

The term federalism refers collectively to several rules and the underlying policies. One rule, codified in the Tenth Amendment to the Constitution, holds that the federal government has only those powers granted to it by the Constitution. Another rule, set forth in the Supremacy Clause, holds that where the federal government does have the power to enact a law, that law is the supreme law of the land and prevails over all inconsistent state and local laws in all American courts. The rules of federalism, in other words, limit the power of both the federal and the state governments.

Federalism represented a compromise between the opposing policies of protecting liberty and ensuring the efficaciousness of the government. A strong centralized government was thought more likely to destroy individual rights, but experience under the Articles of Confederation, the charter of the national government that preceded the Constitution, showed that if power was too decentralized, the national government would be unable to function. The compromise was to give the federal government only certain specified powers but to make it supreme within the ambit of those powers.

Federalism thus reflects the recurrent tension between the community and the individual. The welfare of the community demands an effective government, but protecting the rights of the individual requires limited and thus divided government.

Federalism also illustrates the phenomenon in which a policy stated at a moderately high level of generality is actually a means to an even more general policy. The framers did not consider the division of power between the federal and state governments to be an end in itself but merely a means to the end of preserving liberty.

One of the powers most often relied upon by the federal government in enacting legislation is the commerce clause. The commerce clause provides that Congress shall have the power to regulate commerce “among the several States.” Thus, the constitutional rule creating this power has two elements. First, the statute must be a regulation of commerce. Second, the commerce must be among the several states.

Early in the nineteenth century in Gibbons v. Ogden, the Supreme Court defined these elements.⁵ Commerce was defined as “intercourse,” meaning more than mere trade and extending to navigation. Commerce among the states was defined as “that commerce which affects more states than one.”