rgument, the Court, speaking
by Justice Van Devanter, quoted the following passage from the brief of
the Solicitor-General: "Interstate commerce--if not always, at any rate
when the commerce is transportation--is an act. Congress, of course, can
do anything which, in the exercise by itself of a fair discretion, may
be deemed appropriate to save the act of interstate commerce from
prevention or interruption, or to make that act more secure, more
reliable or more efficient. The act of interstate commerce is done by
the labor of men and with the help of things; and these men and things
are the agents and instruments of the commerce. If the agents or
instruments are destroyed while they are doing the act, commerce is
stopped; if the agents or instruments are interrupted, commerce is
interrupted; if the agents or instruments are not of the right kind or
quality, commerce in consequence becomes slow or costly or unsafe or
otherwise inefficient; and if the conditions under which the agents or
instruments do the work of commerce are wrong or disadvantageous, those
bad conditions may and often will prevent or interrupt the act of
commerce or make it less expeditious, less reliable, less economical and
less secure. Therefore, Congress may legislate about the agents and
instruments of interstate commerce, and about the conditions under
which those agents and instruments perform the work of interstate
commerce, whenever such legislation bears, or in the exercise of a fair
legislative discretion can be deemed to bear, upon the reliability or
promptness or economy or security or utility of the interstate commerce
act."[406]

The Adair Case

But while the idea expressed here that the human agents of commerce, in
the sense of transportation, are instrumentalities of it, and so, in
that capacity, within the protective power of Congress, signalized the
entrance of Congress into the field of labor legislation, the Court was
not at the time prepared to give the idea any considerable scope.
Pertinent in this connection is the case of Adair _v._ United
States,[407] which was decided between the two Employers' Liability
Cases. Here was involved the validity of Sec. 10 of the "Erdman Act" of
1898,[408] by which it was made a misdemeanor for a carrier or agent
thereof to require of an employee, as a condition of employment, that he
should not become or remain a member of a trade union, or to threaten
him with loss of employment if he should