William Strong

“ It seems hardly necessary to argue at length, that, unless the statute can be justified as a legitimate exercise of the police power of the State, it is a usurpation of the power vested exclusively in Congress. It is a plain regulation of inter-state commerce, a regulation extending to prohibition. Whatever may be the power of a State over commerce that is completely internal, it can no more prohibit or regulate that which is inter-state than it can that which is with foreign nations. ”

“ It is not an inspection law. It says to all natural persons and to all transportation companies, 'You shall not bring into the State any Texas cattle or any Mexican cattle or Indian cattle, between March 1 and Dec. 1 in any year, no matter whether they are free from disease or not, no matter whether they may do an injury to the inhabitants of the State or not; and if you do bring them in, even for the purpose of carrying them through the State without unloading them, you shall be subject to extraordinary liabilities.' Such a statute, we do not doubt, it is beyond the power of a State to enact. ”

“ And if, as we have held, State taxation of persons passing from one State to another, or a State tax upon inter-state transportation of passengers, is prohibited by the Constitution because a burden upon it, a fortiori, if possible, is a State tax upon the carriage of merchandise from State to State. Transportation is essential to commerce, or rather it is commerce itself ”