Smith summarizes Spooner’s basic arguments for the unconstitutionality of slavery.

George H. Smith was formerly Senior Research Fellow for the Institute for Humane Studies, a lecturer on American History for Cato Summer Seminars, and Executive Editor of Knowledge Products. Smith’s fourth and most recent book, The System of Liberty, was published by Cambridge University Press in 2013.

In The Unconstitutionality of Slavery (in two parts, 1845 and 1847), Lysander Spooner set out to show “that the constitution of the United States, not only does not recognize or sanction slavery, as a legal institution, but that, on the contrary, it presumes all men to be free; that it positively denies the right of property in man; and that it, of itself, makes it impossible for slavery to have a legal existence in any of the United States.”

It was commonly argued that the Constitution contains three major slavery provisions, though the words “slave” and “slavery” appear nowhere in the document. To the argument that the framers intended to sanction slavery, Spooner replied that their intentions are irrelevant. The only thing that matters is the legal meaning of the words they used, and this brings us to Spooner’s primary rules of textual interpretation that should guide our understanding of the Constitution.

1st, that no intention, in violation of natural justice and natural right (like that to sanction slavery,), can be ascribed to the constitution, unless that intention be expressed in terms that are legally competent to express such an intention; and, 2d, that no terms, except those that are plenary, express, explicit, distinct, unequivocal, and to which no other meaning can be given, are legally competent to authorize or sanction anything contrary to natural right.

In support of these rules, Spooner quoted the following passage from Chief Justice John Marshall’s dissenting opinion in Ogden v. Saunders:

The intention of the instrument must prevail; that this intention must be collected from its words; that its words are to be understood in that sense in which they are generally used by those for whom the Instrument was intended; that its provisions are neither to be restricted into insignificance, nor extended to objects not comprehended in them, nor contemplated by its framers.

Spooner spun out what he believed to be an implication of this passage.

That where words are susceptible of two meanings, one consistent, and the other inconsistent, with justice and natural right, that meaning, and only that meaning, which is consistent with right, shall be attributed to them—unless other parts of the Instrument overrule that interpretation.

There are some obvious gaps here. From Marshall’s statement it does not follow that laws and constitutional provisions should always be understood as favoring individual rights unless there is explicit language to the contrary, so Spooner fortified his position with another passage from a Supreme Court decision.

Where rights are infringed, where fundamental principles are overthrown, where the general system of the laws is departed from, the legislative intention must be expressed with irresistible clearness, to induce a court to effect such objects.

Although this rule has become “the settled doctrine of courts,” it does not quite do the job that Spooner needed. Yet it is good “so far as it goes” insofar as it serves as a “scaffolding, from which to erect a higher standard of law, to wit, that no language or authority whatever can legalize anything inconsistent with natural law.” We thus see how Spooner appealed to natural law as a beacon to guide legal interpretations. For Spooner, contract law—and he regarded the Constitution as a type of contract (for the purpose of his overall argument)—presupposes that contracts are entered into for the benefit of the contracting parties. And since the Preamble to the Constitution specifies “we the people” as the contracting parties, we must assume that blacks and well as whites are among those people. And it would be unreasonable to assume that blacks contracted for their own enslavement.

According to Spooner, no government can legitimately claim powers that are “opposed to justice and natural rights,” so it would conflict with the purpose of law for the judiciary to give to a law anything other than “an honest and innocent meaning.” Moreover, a judge may not appeal to the supposed intentions of a legislature to read into a law unjust features that are not expressly and unambiguously stated in the law itself.

Spooner went into far greater detail about these matters than I have been able to sketch here. But the basic thrust of his argument should be clear: We should not begin with the psychological states of framers and legislators and then surmise the meaning of a constitution or law from those states. Rather, we should begin with the text and, using the most innocent meaning of its words, determine the intentions of the drafters. We must assume that parties to a contract understand the meaning of their contract; and even if they don’t, it is a legal presumption that they do. Thus if future disputes arise, a court must follow commonsense rules in its interpretation of the contract.

It is when Spooner attempted to apply his interpretive rules to the slavery provisions in the Constitution that he ran into serious problems. Consider his understanding of the fugitive slave clause (Art. 4, sect. 2), which reads:

No person, held to service or labor in one State, under the laws thereof, escaping into another, shall, in consequence of any law or regulation therein, be discharged from such service or labor; but shall be delivered up on claim of the party to whom such service or labor may be due.

It was understood during the Constitutional Convention that this clause applied to runaway slaves. Spooner knew this, of course (he was familiar with Madison’s notes), but he denied the relevance of what the delegates meant to say. Their intentions were not germane to the legal meaning of the text. The clause does not mention slaves at all, nor should it be construed as pertaining to slaves. Rather, “It must be construed, if possible, as sanctioning nothing contrary to natural right.” Thus:

If there be any “service or labor” whatever, to which any “persons” whatever may be “held,” consistently with natural right, and which any person may, consistently with natural right, “claim” as his “due” of another, such “service or labor,” and only such is recognized by this provision.

It needs no argument to determine whether the “service or labor,” that is exacted of a slave, is such as can be “claimed,” consistently with natural right, as being “due” from his to his master. And if it cannot be, some other “service or labor” must, if possible, be found for this clause to apply to.

Here see a good illustration of Spooner’s method. Having disqualified a proslavery interpretation of this clause because it would conflict with natural right, Spooner went in search of some other meaning. And he found what he was looking for in the status of indentured servants. He then added a number of arguments to support his claim that the clause refers not to slaves but to indentured servants, even though he knew that this was not the original intent of the framers. The ingenuity of Spooner’s argument cannot be gainsaid, but it smacks of partisan skullduggery.

Even more egregious was Spooner’s explanation of the three‐​fifths rule (Art. I, sect. 2), which begins:

Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons.

Common sense would dictate that “free Persons” stood in contrast to unfree persons, so “all other Persons” clearly meant slaves. This is how the clause was understood by delegates to the Convention. But Spooner would have none of this. He curiously and repeatedly claimed that, prior to the Convention, “free Persons” was never used (either in common law or in American legal documents) in contrast to slaves. Instead, “free persons” referred to Americans with the full rights of citizenship, in contrast to immigrants and others who did not enjoy all the privileges of citizenship. Spooner argued for this point extensively; but Wendell Phillips, in his critique (Review of Lysander Spooner’s Essay on the Unconstitutionality of Slavery) easily provided many quotations that contradicted Spooner’s outlandish claim.

So how should we assess Lysander Spooner’s attempt to prove the unconstitutionality of slavery? In my judgment, it was a failure, if a noble one. Although his two tracts contain many theoretical gems that are well worth reading, his ultimate goal was never achieved. It contains too many unreal assumptions, such as the claim that those who actually voted for the Constitution—the people whose intentions did matter for Spooner—did not understand it to be proslavery. As Wendell Phillips said of this assertion, “We hardly know of a more daring flight of genius in the whole range of modern fiction than this.”