|1.||That Congress is impotent to control the intrastate charges of an interstate carrier even to the extent necessary to prevent injurious discrimination against interstate traffic; and|
|2.||(2) That, if it be assumed that Congress has this power, still it has not been exercised, and hence the action of this commission exceeded the limits of the authority which has been conferred upon it. . . .|
Congress is empowered to regulate, -- that is, to provide the law for the government of interstate commerce; to enact "all appropriate legislation" for its "protection and advancement" ( The Daniel Ball, 10 Wall. 557, 564); to adopt measures "to promote its growth and insure its safety" ( Mobile County v. Kimball, 102 U.S. 691, 696); "to foster, protect, control, and restrain" ( Second Employers' Liability Cases [Mondou v. New York, N. H. & H. R. Co.] 223 U.S. 1, 47, 53, 54). Its authority, extending to these interstate carriers as instruments of interstate commerce, necessarily embraces the right to control their operations in all matters having such a close and substantial relation to interstate traffic that the control is essential or appropriate to the security of that traffic, to the efficiency of the interstate service, and to the maintenance of conditions under which interstate commerce may be conducted upon fair terms and without molestation or hindrance. As it is competent for Congress to legislate to these ends, unquestionably it may seek their attainment by requiring that the agencies of interstate commerce shall not be used in such manner as to cripple, retard, or destroy it. The fact that carriers are instruments of intrastate commerce, as well as of interstate commerce, does not derogate from the complete and paramount authority of Congress over the latter or preclude the Federal power from being exerted to prevent the intrastate operations of such carriers from being made a means of injury to that which has been confided to Federal care. Wherever the interstate and intrastate transactions of carriers are so related that the government of the one involves the control of the other, it is Congress, and not the State, that is entitled to prescribe the final and dominant rule, for otherwise Congress would be denied the exercise of its constitutional authority, and the State, and not the Nation, would be supreme within the national field.
. . . This is not to say that Congress possesses the authority to regulate the internal commerce of a State, as such, but that it does possess the power to foster and protect interstate commerce, and to take all measures necessary or appropriate to that end, although intrastate transactions of interstate carriers may thereby be controlled.
This principle is applicable here. We find no reason to doubt that Congress is entitled to keep the highways of interstate communication open to interstate traffic upon fair and equal terms.