Effective Regulation of Public Utilities
To give entrance to [protectionism] would be to invite a speedy end of our national solidarity. The Constitution was framed under the dominion of a political philosophy less parochial in range. It was framed upon the theory that the peoples of the several states must sink or swim together, and that in the long run prosperity and salvation are in union and not division.
Baldwin v. G. A. F. Seelig, Inc., 294 U.S. 511, 523 (1935)