cised, does not touch interstate commerce or its instrumentalities, and can only have an effect upon such commerce by reason of the reflex and remote results of the exertion of the lawful power, it cannot be said, without a contradiction in terms that the power exercised is a regulation, because a direct burden upon commerce * * * The question whether a burden is direct and therefore constitutes a regulation of interstate commerce is to be determined by ascertaining whether the power exerted is lawful, generally speaking, and then by finding whether its exercise in the particular case was such as to cause it to be illegal, because directly burdening interstate commerce. If in a given case the power be lawful and the mode in which it is exercised be not such as to directly burden, there is no regulation of commerce, although as an indirect result of the exertion of the lawful power some effect may be produced upon commerce." But, of course, the mere fact that a result merely "may be produced" and as "an indirect result" cannot even at common law amount to the "dangerous probability" constituting "tendency" with which the law deals.
Or, in a nutshell, as is said by the same justice in Pabst vs. Crenshaw:[1] "The distinction between direct and indirect burdens upon interstate commerce, by means of which the harmonious working of our constitutional system has been made possible."
But, of course, it must not be forgotten, as already pointed out, that no exercise of power is lawful if used to accomplish an illegal purpose, or that really tends to the accomplishment of it, or the
- ↑ 198 U. S. 30 (1905).
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