The constitutionality of this provision, which has since been adopted by several of the Southern States, has never been judicially determined. The clause with which it is thought to conflict, is that which provides, that “the citizens of each State shall be entitled to all the privileges and immunities of citizens in the several States.” Now, if residence and the right to be protected in acquiring and transmitting property under the laws be sufficient to constitute citizenship, the free negro population of every Northern State would be entitled to some privileges in the State of Missouri; and, assuredly, when a party is entitled to exercise certain rights within a given territory, it can never be legal to deprive him of those rights, by forbidding him to enter it. And even if these qualifications are insufficient to constitute citizenship, (a theory which would exclude a large proportion of the white population in some of the Southern States,) yet in a few of the free States the right of voting is at present added to them; and in these cases, at least, if the clause be not doomed to remain forever a dead letter, it would seem to find its application. On the other hand, it was urged with great force, that if the Legislature of a State esteem a certain class of population dangerous to its existence, it must be entitled by the first principle of self-preservation--the foundation both of national and individual existence--to exclude them from its midst. The clause in the Constitution cannot mean that every citizen of each State is entitled to become such in every other State. This is notoriously untrue. In some States freehold qualifications are required for voters; in others not. In some there are restraints upon the acquisition of property, which in others do not exist. Where, then, is the line to be drawn between constitutional and unconstitutional differences? Each State may determine the qualifications necessary for its voters--why may not one of them be a peculiar color? Each State may exclude from its borders the professors of particular occupations, which may be distasteful to it, or which it may fancy to be dangerous; why not those who have, at any time, exercised such occupations--which would amount to the same thing as the exclusion of an obnoxious race?