Originalism today is predominant yet divided. Courts regularly invoke original meaning, but originalist scholars still debate what interpretation itself requires. At the center of that division is the interpretation-construction distinction. Interpretation is the process of determining the meaning of a constitutional provision. Construction begins only when that meaning is deemed indeterminate—that is, when it is thought to run out—and the decision must be made on grounds other than the provision’s original meaning.

This distinction has generated one of the most important controversies in contemporary originalist theory: how large is the construction zone? That question may sound technical, but it is crucial to originalism because it determines how much constitutional law is governed by original meaning and how much is left to judicial discretion, normative considerations, or other methods of non-constitutional decision-making.

If the construction zone is large, originalism governs only the clearest provisions, while judges resolve many important disputes by moral or policy judgment. Thus, construction can become a form of living constitutionalism. A small construction zone, by contrast, means that the Constitution functions as a document whose meaning can be recovered and applied through interpretation.

The Construction Zone and the Language of the Law

Original methods originalism explains why that construction zone is much smaller than is often supposed. The Constitution must be interpreted not only according to the meaning of its words at the time of enactment, but also according to the interpretive rules deemed applicable to a document of that kind at that time. Those rules are not optional. They are constitutive of meaning. If modern interpreters employ different interpretive rules from those the enactors would have deemed applicable, they will produce a different meaning from the one the Constitution had when it was enacted.

The Constitution is not written simply in lay language, but in the language of the law. It is a legal instrument, expressly made the “supreme Law of the Land,” filled with legal terms, legal forms, and references to legal interpretive rules. The purpose of technical legal language and legal interpretive rules is to reduce uncertainty by providing more precise definitions and more determinate methods. The language of the law, therefore, enlarges the zone of interpretation and narrows the zone of construction.

If ambiguity can be resolved by selecting the better legal meaning, then the construction zone is small.

For minimizing the construction zone, the most important rule is what we call the 51–49 rule. When the evidence is close—when it seems that an issue could be decided in either of two ways—the interpreter must choose the stronger interpretation, even if it is only slightly stronger. The rule does not assume that difficult questions are easy. Nor that all interpreters will agree. In fact, in close cases it is likely that interpreters will disagree about which interpretation is stronger. But the mere existence of disagreement does not establish indeterminacy. The 51–49 rule allows ambiguity to be resolved by selecting the better interpretation, and therefore close cases do not require interpreters to consider the normative or extraconstitutional considerations that the construction zone requires.

The 51-49 rule is central because ambiguity is the principal route by which cases become a matter of construction rather than interpretation. If every close question creates ambiguity, then the construction zone becomes large, and original meaning governs only a narrow set of cases. But if the original legal rules require interpreters to select the interpretation with stronger support, then many questions said to require construction are instead resolved by interpretation. The Constitution’s meaning does not run out merely because the evidence is contested.

Some scholars have challenged the rule, either directly or by implication. Some suggest that determining original public meaning requires broad public agreement. Others argue that early disagreements over issues such as the Bank of the United States show that the Constitution lacked a determinate meaning on important questions. The common error in these objections is to confuse disagreement about meaning with the absence of legal meaning. Law routinely delivers determinacy through agreed procedures despite disagreement about outcomes.

The Evidence for the 51–49 Rule

The originalist evidence for the 51–49 rule is strong. It begins with leading figures from both the Federalist and Democratic-Republican camps. Fisher Ames, a key Federalist and influential member of the Massachusetts Ratification Convention, articulated the principle during the debate over the First Bank of the United States. Ames declared that he had “no desire to extend the powers granted by the constitution beyond the limits prescribed to them.” Yet he recognized that “in cases where there was doubt as to its meaning and intention,” he had a duty “to consult his conscience and judgment to solve them.” Even when doubts remained between two different interpretations, Ames said he would adopt the reading “least involved in doubt.” That is the 51–49 rule.

Equally significant, Thomas Jefferson—the preeminent Democratic-Republican—insisted that “on every question of construction” interpreters should carry themselves back to the time when the Constitution was adopted, recollect the spirit manifested in the debates, and rather than squeeze a meaning out of the text or invent one against it, conform to “the probable one, in which it passed.” Ames and Jefferson did not agree on much. But they agreed on this method for resolving constitutional ambiguity. The interpreter should not invent; he should select the probable meaning.

The rule also has an obvious intuitive appeal. Where there is evidence on both sides of an issue, one should select the interpretation with the stronger evidence. Obviously, one should not choose the interpretation with weaker evidence. The law often employed this common-sense rule, as it did in civil litigation, where the plaintiff needed only to prove his case by a preponderance of the evidence.

To be sure, the law did not always decide every legal question by simply counting the evidence. Special legal rules sometimes affected which interpretation was stronger. In criminal cases, for example, the rule of lenity favors the defendant. But the rule of lenity is itself a rule of interpretation. It helps determine which reading the law adopts, instructing the interpreter to decide close cases in favor of the defendant. But even here the law does not run out or require construction. It merely changes the quantum of evidence required to decide the case against the criminal defendant. And where no special rule applies—as is usually the case—the case is decided based on a simple balancing of the evidence.

The cases around the time of the Framing provide salient evidence because courts acknowledged interpretive difficulty and nevertheless selected the better legal reading. Courts repeatedly wrestled with difficult questions of interpretation. They faced two plausible readings, admitted that the choice was difficult, and nevertheless resolved the issue by weighing the evidence and applying legal interpretive rules. Since courts do not readily acknowledge that a question is close, these cases are strong evidence that they were applying a 51—49 rule.

Originalism need not surrender hard cases to normative judgment. It can remain interpretive, not normative, all the way down.

United States v. Fisher is a leading example. The question was whether a 1797 statute gave the United States priority in bankruptcy proceedings with respect to all its debtors or only to a narrower class of receivers of public money. Chief Justice Marshall adopted the broader reading, but he acknowledged the strength of the narrower one. He recognized that the statute created “much embarrassment,” that the opposing argument had “great strength of reasoning,” and that he was addressing a “doubtful statute” requiring mature consideration. Justice Bushrod Washington’s contrary view in favor of the narrow reading relied on the statute’s structure, title, and the canon against redundancy. Nonetheless, Marshall concluded that the broader reading was the better one. The section at issue, unlike the rest of the act, dealt not only with the duties of receivers of public money but with a distinct subject—the government’s priority in bankruptcy—and it described the debtors covered in broad terms. Fisher is not a case of plain meaning triumphing over a clearly inferior alternative. It is a case of a court selecting the better interpretation of a doubtful statute.

United States v. Palmer supplies another important example, in which Marshall resolved two close questions under a piracy statute. To keep this brief, we consider only the first question—whether robbery on the high seas was a capital offense. The statute made piracy capital and reached murder, robbery, and any other offense that would be punishable by death if committed on land. The defendant offered a plausible reading that the “any other offense” language modified robbery—so that robbery at sea was capital only if robbery on land was, which under federal law it was not. Marshall acknowledged that this reading was “entitled to great respect,” especially because the statute inflicted capital punishment. Yet he rejected it, concluding that Congress had named murder and robbery separately. Many other cases at the state and federal level adopt a similar approach.

Evidence from leading treatises reinforces the point. Emmerich de Vattel, an eighteenth-century natural law theorist who influenced the Founders deeply, wrote in his Law of Nations that “in all human affairs, when there is a want of certainty, we ought to follow probability.” If many interpretations present themselves, he said, one should prefer the interpretation that appears most agreeable to the intention with which the instrument was framed. English academic Thomas Rutherforth similarly recognized that common topics of interpretation may appear on both sides with enough probability to make certainty difficult but still directed interpreters to decide according to what rational conjectures show to be most probably the enactor’s meaning. US Supreme Court Justice Joseph Story stated the rule in constitutional terms: when constitutional words are susceptible to two senses, one strict and one enlarged, the interpretation should be adopted that is most consonant with the apparent objects and intent of the Constitution.

Objections

Nor is there substantial contrary evidence. The most significant possible rival is what one of us has called “the duty of clarity,” under which a court should hold a statute unconstitutional only when it clearly violates the Constitution. But even if one accepts that rule (as one of us does), it does not conflict with the 51–49 rule. The duty of clarity is best understood as a rule about judicial power. It governs the extent to which courts should second-guess legislatures. It is not a pure rule of interpretation in the first instance. Thus, on this view, a court might concede that a particular interpretation of the Constitution is slightly better than another, but nevertheless decline to overturn legislation on that basis, because it is not sufficiently sure that the legislature’s was mistaken. But when the legislature (or the executive or a citizen) interprets the Constitution, the 51-49 rule requires that they follow the interpretation believed more likely. And this holds even if one believes that the courts must give some modicum of deference to the legislature’s decision.