The Commerce Clause contains no reference to trade between the States and the Territories or the District of Columbia, or the Territories inter se. In general, however, the courts have treated the District of Columbia and the Territories as "States" within the mearing of the Clause.79

Congress having exclusive jurisdiction within and over the District and the Territories, there of course cannot arise, as to them, the objection that federal regulations extend to matters that are of domestic concern.