products of child
labor--pernicious because it bore "a real and substantial relation" to
the existence of child labor employment in some States and constituted a
direct inducement to its spread to other States. Deprived of the
interstate market which this decision secured to it, child labor could
not exist.

INTERSTATE COMMERCE IN STOLEN GOODS BANNED

In Brooks _v._ United States,[516] decided in 1925, the Court, in
sustaining the National Motor Vehicle Theft Act of 1919,[517] materially
impaired the _ratio decidendi_ of Hammer _v._ Dagenhart. At the outset
of his opinion for the Court, Chief Justice Taft stated the general
proposition that "Congress can certainly regulate interstate commerce to
the extent of forbidding and punishing the use of such commerce as an
agency to promote immorality, dishonesty or the spread of any evil or
harm to the people of other States from the State of origin." This
statement was buttressed by a review of previous cases, including the
explanation that the goods involved in Hammer _v._ Dagenhart were
"harmless" and did not spread harm to persons in other States. Passing
then to the measure before the Court, the Chief Justice noted "the
radical change in transportation" brought about by the automobile, and
the rise of "elaborately organized conspiracies for the theft of
automobiles * * *, and their sale or other disposition" in another
police jurisdiction from the owner's. This, the opinion declared, "is a
gross misuse of interstate commerce. Congress may properly punish such
interstate transportation by anyone with knowledge of the theft, because
of its harmful result and its defeat of the property rights of those
whose machines against their will are taken into other
jurisdictions."[518]

The Motor Vehicle Act was sustained, therefore, mainly as protective of
owners of automobiles, that is to say, of interests in "the State of
origin." It was designed to repress automobile thefts, and that
notwithstanding the obvious fact that such thefts must necessarily occur
before transportation of the thing stolen can take place, that is, under
the formula followed in Hammer _v._ Dagenhart, before Congress's power
over interstate commerce becomes operative. Also, the Court took
cognizance of "elaborately organized conspiracies" for the theft and
disposal of automobiles across State lines--that, to say, of a
widespread traffic in such property.

THE DARBY CASE

The formal overruling of Ham