that in construing the constitution, "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." On this principle of construction, there is not the least
authority for saying that this provision for "the importation of
persons," authorized the importation of them as slaves. To give it this
meaning, requires the same stretching of words _towards the wrong_, that
is applied, by the advocates of slavery, to the words "service or
labor," and the words "free" and "all other persons."

Another reason, which makes it necessary that this construction should
be placed upon the word "_importation_," is, that the clause contains no
other word that describes the immigration of foreigners. Yet that the
clause related to the immigration of foreigners _generally_, and that it
restrained congress, (up to the year 1808,) from prohibiting the
immigration of foreigners generally, there can be no doubt.

The object, and the only _legal_ object, of the clause was to restrain
congress from so exercising their "power of regulating commerce with
foreign nations, and among the several states, and with the Indian
tribes"--(which power has been decided by the supreme court of the
United States, to include a power over navigation and the transportation
of passengers in boats and vessels[21])--as to obstruct the introduction
of new population into such of the states as were desirous of increasing
their population in that manner. The clause does not imply at all, that
the population, which the states were thus to "admit," was to be a slave
population.

The word "importation," (I repeat,) is the only word in the clause, that
applies to persons that were to _come into_ the country from foreign
nations. The word "_migration_" applies only to those who were to _go
out from_ one of our own states or territories into another.
"_Migration_" is the act of _going out_ from a state or country; and
differs from immigration in this, that immigration is the act of _coming
into_ a state or country. It is obvious, therefore, that the
"_migration_," which congress are here forbidden to prohibit, is simply
the _going out_ of persons from one of our own states or territories
into another--(for that is the only "_migration_" that could come within
the jurisdiction of congress)--and that it has