t that
the existence of an economic emergency justified the exercise of what
Chief Justice Hughes called "extraconstitutional authority."[23]

In 1941 the Court came full circle in its exposition of this amendment.
Having returned to the position of John Marshall four years earlier when
it sustained the Social Security[24] and National Labor Relations
Acts,[25] it explicitly restated Marshall's thesis in upholding the Fair
Labor Standards Act in United States _v._ Darby.[26] Speaking for a
unanimous Court, Chief Justice Stone wrote: "The power of Congress over
interstate commerce 'is complete in itself, may be exercised to its
utmost extent, and acknowledges no limitations other than are prescribed
in the Constitution.' * * * That power can neither be enlarged nor
diminished by the exercise or non-exercise of state power. * * * It is
no objection to the assertion of the power to regulate interstate
commerce that its exercise is attended by the same incidents which
attend the exercise of the police power of the states. * * * Our
conclusion is unaffected by the Tenth Amendment which * * * states but a
truism that all is retained which has not been surrendered."[27]

Police Power

But even prior to 1937 not all measures taken to promote objectives
which had traditionally been regarded as the responsibilities of the
States had been held invalid. In Hamilton _v._ Kentucky Distilleries
Co.,[28] a unanimous Court, speaking by Justice Brandeis, upheld "War
Prohibition", saying: "That the United States lacks the police power,
and that this was reserved to the States by the Tenth Amendment, is
true. But it is none the less true that when the United States exerts
any of the powers conferred upon it by the Constitution, no valid
objection can be based upon the fact that such exercise may be attended
by the same incidents which attend the exercise by a State of its police
power."[29] And in a series of cases, which today seem irreconcilable
with Hammer _v._ Dagenhart, it sustained federal laws penalizing the
interstate transportation of lottery tickets,[30] of women for immoral
purposes,[31] of stolen automobiles,[32] and of tick-infested
cattle.[33] It affirmed the power of Congress to punish the forgery of
bills of lading purporting to cover interstate shipments of
merchandise,[34] to subject prison made goods moved from one State to
another to the laws of the receiving State,[35] and to regulate
prescriptions for the medicin