ept as applied in the District of Columbia and other areas over which
Congress has exclusive authority, a federal statute penalizing the sale
of dangerous illuminating oils.[13] The Court did not refer to the Tenth
Amendment. Instead, it asserted that the "* * * express grant of power
to regulate commerce among the States has always been understood as
limited by its terms; and as a virtual denial of any power to interfere
with the internal trade and business of the separate States; except,
indeed, as a necessary and proper means for carrying into execution some
other power expressly granted or vested."[14] Similarly, in the
Employers' Liability Cases,[15] an act of Congress making every carrier
engaged in interstate commerce liable to "any" employee, including those
whose activities related solely to intrastate activities, for injuries
caused by negligence, was held unconstitutional by a closely divided
Court, without explicit reliance on the Tenth Amendment. Not until it
was confronted with the Child Labor Law, which prohibited the
transportation in interstate commerce of goods produced in
establishments in which child labor was employed, did the Court hold
that the State police power was an obstacle to adoption of a measure
which operated directly and immediately upon interstate commerce. In
Hammer _v._ Dagenhart,[16] five members of the Court found in the Tenth
Amendment a mandate to nullify this law as an unwarranted invasion of
the reserved powers of the States. This decision was expressly overruled
in United States _v._ Darby.[17]

During the twenty years following Hammer _v._ Dagenhart, a variety of
measures designed to regulate economic activities, directly or
indirectly, were held void on similar grounds. Excise taxes on the
profits of factories in which child labor was employed,[18] on the sale
of grain futures on markets which failed to comply with federal
regulations,[19] on the sale of coal produced by nonmembers of a coal
code established as a part of a federal regulatory scheme,[20] and a tax
on the processing of agricultural products, the proceeds of which were
paid to farmers who complied with production limitations imposed by the
Federal Government,[21] were all found to invade the reserved powers of
the States. In Schechter Poultry Corporation _v._ United States[22] the
Court, after holding that the commerce power did not extend to local
sales of poultry, cited the Tenth Amendment to refute the argumen