Duties upon exports, though they may answer in some particulars a
convenience to the country which imposes them, are certainly not things
to be contended for, as if the very being of a State was interested in
preserving them. Where there is a kind of monopoly they may sometimes
be ventured upon, but even there perhaps more is lost by imposing such
duties, than is compensated for by any advantage. Where there is not a
species of monopoly, no policy can be more absurd. The American States,
are so circumstanced that some of the States necessarily export part of
the produce of neighboring ones. Every duty laid upon such exported
produce operates in fact as a tax by the exporting State upon the
non-exporting State. In a system expressly formed to produce concord
among all, it would have been very unwise to have left such a source
of discord open; and upon the same principle, and to remove as much as
possible every ground of discontent, Congress itself are prohibited
from laying duties on exports, because by that means those States which
have a great deal of produce to export would be taxed much more heavily
than those which had little or none for exportation.