Expressio unius est exclusio alterius

Expressio unius est exclusio alterius is a rule of interpretation holding that the specification of one thing may exclude others. Its application in the constitutional arguments here is conditional, not automatic: enumeration can establish a genuine limit when the text and structure make that limit meaningful, but a provision requiring a practice in one setting does not by itself forbid it elsewhere. The maxim’s significance lies in this distinction between a real boundary and an inference drawn too broadly from silence.

The maxim and the civil-jury dispute

The maxim appears in a dispute over whether the proposed Constitution’s express provision for jury trials in criminal cases impliedly prohibited jury trials in civil cases. Opponents argued from the Constitution’s silence on civil causes that the absence of an express guarantee amounted to an exclusion. The argument treated specification as an absolute rule: because criminal jury trials were named, civil jury trials must have been left out.

The answer tests that inference against the ordinary meaning and purpose of the provision. Requiring the legislature to submit criminal causes to juries, the argument maintains, does not deprive it of authority to permit the same mode of trial in other cases. A command to do one thing is not naturally read as a prohibition on another compatible thing that the legislature already had power to do. The criminal-trial provision removes discretion by making jury trial obligatory in that class; it does not remove the discretion to use juries in civil causes.

The distinction is between excluding an obligation and excluding an authority. The specification can mean that civil jury trials are not constitutionally required, without meaning that Congress lacks power to provide them. On this reading, the maxim cannot establish that civil jury trials have been abolished. The Constitution’s silence leaves the national legislature free to choose a mode of trial in civil cases within its jurisdiction.

When enumeration marks a boundary

The argument does not discard the maxim. Instead, it identifies circumstances in which specification does exclude what has not been specified. The proposed plan grants the national legislature authority over enumerated subjects; that particular list excludes a claim to general legislative authority. If Congress already possessed general authority over every subject, the affirmative grant of particular powers would be redundant and pointless. Here, giving the list limiting force preserves the reason for its inclusion.

The same structural reasoning applies to the federal judiciary. The Constitution assigns federal courts jurisdiction over particular classes of cases. Naming those objects of jurisdiction sets the limits beyond which the federal courts cannot reach; otherwise, the enumeration would do no work. In these examples, the maxim supports a boundary because the Constitution’s institutional design gives the specification a limiting function.

The maxim therefore turns on what is being specified and what follows from the surrounding structure. A list of delegated powers can exclude unlisted powers because the grant is particular rather than general. A stated requirement for criminal jury trials, by contrast, establishes a requirement in criminal cases without negating legislative discretion in civil cases. Treating both provisions as identical applications of the maxim would erase the difference between the scope of a grant and the placement of a mandatory rule.

The married-woman example

A hypothetical state law makes the distinction concrete. Suppose a married woman initially has no power to convey her estate, and the legislature authorizes her to do so by deed executed before a magistrate. Because she lacked a prior power of alienation, the prescribed method can operate as an exclusion of other methods: the law gives her a new capacity and specifies how she may exercise it.

Now suppose a later provision requires the consent of three of her nearest relations for a conveyance of property above a stated value. That additional requirement does not imply that she cannot obtain her relations’ approval for a conveyance of lesser value. The law has imposed a condition on one category; it has not thereby forbidden an otherwise available act in another. The example isolates the relevant question: whether the specified case creates a new authority or condition, or merely makes one practice compulsory in a particular class of cases.

This hypothetical answers the civil-jury objection by analogy. The Constitution’s requirement of jury trial in criminal cases makes that procedure compulsory there. It does not follow that the legislature is disabled from authorizing juries in civil cases. The inference of abolition would confuse a specification that restricts an existing discretion with one that establishes a specific obligation while leaving other discretion intact.

The maxim as a method of constitutional construction

The proposed method treats rules of interpretation as instruments of common sense rather than mechanical formulas. Their proper application depends on whether the result fits the source from which the rules derive and the work the provision performs. Applied without regard to those considerations, the maxim can turn a text’s silence into a prohibition the text does not state and its structure does not require.

That approach also distinguishes the Constitution’s express allocation of powers from the consequences of particular procedural guarantees. Enumerating legislative or judicial authority makes the list’s boundaries meaningful. Providing for criminal juries protects a required mode of trial without necessarily withholding authority to use that mode elsewhere. The same interpretive maxim thus yields different results because the provisions do different constitutional work.

The conclusion is that the proposed Constitution does not abolish civil jury trial by silence. Civil controversies within the jurisdiction of state courts remain governed by state constitutions and laws; the argument also observes that the federal judiciary would not take cognizance of the great body of disputes between citizens of the same state, including most land controversies, subject to stated exceptions. The maxim remains useful for identifying the limits of enumerated federal powers and jurisdiction, but it cannot turn every express provision into an implied prohibition of what it leaves unmentioned.