Mahlon Pitney, Wagner v. City of Covington — Opinion of the Court
“ Of course the transportation of plaintiffs' goods across the state line is of itself interstate commerce; but it is not this that is taxed by the city of Covington, nor is such commerce a part of the business that is taxed, or anything more than a preparation for it. So far as the itinerant vending is concerned, the goods might just as well have been manufactured within the state of Kentucky; to the extent that plaintiffs dispose of their goods in that kind of sales, they make them the subject of local commerce ”
