Admitting this construction of the Constitution, it is alleged that the power by which Congress excluded slavery from the States north-west of the river Ohio, is suspended in respect to the States that may be formed in the province of Louisiana. The article of the treaty referred to declares: "That the inhabitants of the territory shall be incorporated in the Union of the United States, and admitted as soon as possible; according to the principles of the Federal Constitution, to the enjoyment of all rights, advantages, and immunities of citizens of the United States; and in the meantime, they shall be maintained and protected in the free enjoyment of their liberty, property, and the religion which they profess."
Although there is want of precision in the article, its scope and meaning can not be misunderstood. It constitutes a stipulation by which the United States engage that the inhabitants of Louisiana should be formed into a State or States, and as soon as the provisions of the Constitution permit, that they should be admitted as new States into the Union on the footing of the other States; and before such admission, and during their territorial government, that they should be maintained and protected by Congress in the enjoyment of their liberty, property, and religion. The first clause of this stipulation will be executed by the admission of Missouri as a new State into the Union, as such admission will impart to the inhabitants of Missouri "all the rights, advantages, and immunities" which citizens of the United States derive from the Constitution thereof; these rights may be denominated Federal rights, are uniform throughout the Union, and are common to all its citizens: but the rights derived from the Constitution and laws of the States, which may be denominated State rights, in many particulars differ from each other. Thus, while the Federal rights of the citizens of Massachusetts and Virginia are the same, their State rights are dissimilar and different, slavery being forbidden in one, and permitted in the other State. This difference arises out of the Constitutions and laws of the two States, in the same manner as the difference in the rights of the citizens of these States to vote for representatives in Congress arises out of the State laws and Constitution. In Massachusetts, every person of lawful age, and possessing property of any sort, of the value of two hundred dollars, may vote for representatives to Congress. In Virginia, no person can vote for representatives to Congress, unless he be a freeholder. As the admission of a new State into the Union confers upon its citizens only the rights denominated Federal, and as these are common to the citizens of all the States, as well of those in which slavery is prohibited, as of those in which it is allowed, it follows that the prohibition of slavery in Missouri will not impair the Federal rights of its citizens, and that such prohibition is not sustained by the clause of the treaty which has been cited.
As all nations do not permit slavery, the term property, in its common and universal meaning, does not include or describe slaves. In treaties, therefore, between nations, and especially in those of the United States, whenever stipulations respecting slaves were to be made, the word "negroes," or "slaves," have been employed, and the omission of these words in this clause, increases the uncertainty whether, by the term property, slaves were intended to be included. But admitting that such was the intention of the parties, the stipulation is not only temporary, but extends no further than to the property actually possessed by the inhabitants of Missouri, when it was first occupied by the United States. Property since acquired by them, and property acquired or possessed by the new inhabitants of Missouri, has in each case been acquired under the laws of the United States, and not during and under the laws of the province of Louisiana. Should, therefore, the future introduction of slaves into Missouri be forbidden, the feelings of the citizens would soon become reconciled to their exclusion, and the inconsiderable number of slaves owned by the inhabitants at the date of the cession of Louisiana, would be emancipated or sent for sale into States where slavery exists.
It is further objected, that the article of the act of admission into the Union, by which slavery should be excluded from Missouri, would be nugatory, as the new State in virtue of its sovereignty would be at liberty to revoke its consent, and annul the article by which slavery is excluded.
Such revocation would be contrary to the obligations of good faith, which enjoins the observance of our engagements; it would be repugnant to the principles on which government itself is founded; sovereignty in every lawful government is a limited power, and can do only what it is lawful to do. Sovereigns, like individuals, are bound by their engagements, and have no moral power to break them. Treaties between nations repose on this principle. If the new State can revoke and annul an article concluded between itself and the United States, by which slavery is excluded from it, it may revoke and annul any other article of the compact; it may, for example, annul the article respecting public lands, and in virtue of its sovereignty, assume the right to tax and to sell the lands of the United States. There is yet a more satisfactory answer to this objection. The judicial power of the United States is co-extensive with their legislative power, and every question arising under the Constitution or laws of the United States, is recognizable by the judiciary thereof. Should the new State rescind any of the articles of compact contained in the act of admission into the Union, that, for example, by which slavery is excluded, and should pass a law authorizing slavery, the judiciary of the United States on proper application, would immediately deliver from bondage, any person retained as a slave in said State. And, in like manner, in all instances affecting individuals, the judiciary might be employed to defeat every attempt to violate the Constitution and laws of the United States.
If Congress possess the power to exclude slavery from Missouri, it still remains to be shown that they ought to do so. The examination of this branch of the subject, for obvious reasons, is attended with peculiar difficulty, and cannot be made without passing over arguments which, to some of us, might appear to be decisive, but the use of which, in this place, would call up feelings, the influence of which would disturb, if not defeat, the impartial consideration of the subject.
Slavery, unhappily, exists within the United States. Enlightened men, in the States where it is permitted, and everywhere out of them, regret its existence among us, and seek for the means of limiting and of mitigating it. The first introduction of slaves is not imputable to the present generation, nor even to their ancestors. Before the year 1642, the trade and ports of the colonies were open to foreigners equally as those of the mother country; and as early as 1620, a few years only after the planting of the colony of Virginia, and the same year in which the first settlement was made in the old colony of Plymouth, a cargo of negroes was brought into and sold as slaves in Virginia by a foreign ship. From this beginning, the importation of slaves was continued for nearly two centuries. To her honor, Virginia, while a colony, opposed the importation of slaves, and was the first State to prohibit the same, by a law passed for this purpose in 1778, thirty years before the general prohibition enacted by Congress in 1808. The laws and customs of the States in which slavery has existed for so long a period, must have had their influence on the opinions and habits of the citizens, which ought not to be disregarded on the present occasion.
When the general convention that formed the Constitution took this subject into their consideration, the whole question was once more examined; and while it was agreed that all contributions to the common treasury should be made according to the ability of the several States to furnish the same, the old difficulty recurred in agreeing upon a rule whereby such ability should be ascertained, there being no simple standard by which the ability of individuals to pay taxes can be ascertained. A diversity in the selection of taxes has been deemed requisite to their equalization. Between communities this difficulty is less considerable, and although the rule of relative numbers would not accurately measure the relative wealth of nations, in States in the circumstances of the United States, whose institutions, laws, and employments are so much alike, the rule of numbers is probably as near equal as any other simple and practical rule can be expected to be (though between the old and new States its equity is defective),—these considerations, added to the approbation which had already been given to the rule, by a majority of the States, induced the convention to agree that direct taxes should be apportioned among the States, according to the whole number of free persons, and three-fifths of the slaves which they might respectively contain.
The rule for apportionment of taxes is not necessarily the most equitable rule for the apportionment of representatives among the States; property must not be disregarded in the composition of the first rule, but frequently is overlooked in the establishment of the second. A rule which might be approved in respect to taxes, would be disapproved in respect to representatives; one individual possessing twice as much property as another, might be required to pay double the taxes of such other; but no man has two votes to another's one; rich or poor, each has but a single vote in the choice of representatives.