Louis Brandeis

“ The vice of the legislation is dramatically exposed by the fact that the state of Oregon had issued its certificate which may be deemed equivalent to a legislative declaration that, despite existing facilities, public convenience and necessity required the establishment by Buck of the auto stage line between Seattle and Portland. Thus, the provision of the Washington statute is a regulation, not of the use of its own highways, but of interstate commerce. Its effect upon such commerce is not merely to burden, but to obstruct, it. ”

“ It is that section 4 is unconstitutional because use of the highways for interstate commerce is denied unless the prescribed certificate shall have been secured. Buck applied for a certificate. Thus he invoked the exercise of the power which he now assails. One who invokes the provisions of law may not thereafter question its constitutionality. The argument is unsound. It is true that one cannot in the same proceeding both assail a statute and rely upon it. ”

“ Its primary purpose is not regulation with a view to safety or to conservation of the highways, but the prohibition of competition. It determines, not the manner of use, but the persons by whom the highways may be used. It prohibits such use to some persons, while permitting it to others for the same purpose and in the same manner. ”