A monopolist still has cause to worry even though he be secure from competitors and his product be free from the competition of substitutes. Despite the doctrine of laissez faire, society through government sets limits beyond which monopoly may not go. It undertakes, when all other methods have failed, to curb exorbitant rewards and unfair practices. In fact, as we have already seen, the people of the United States have firmly concluded that there is no possibility of some industries being regulated either by competition or by substitution. Accordingly, in these cases the people have turned to government regulation. For many years the opinion prevailed in the United States that the best way to control a railroad was to encourage the building of competing lines. In time it was seen that such a plan was not only inadequate but also undesirable. Then it was proposed that the government should provide, not competing railroads, but substitute transportation lines in the form of canals. This too was put aside as impracticable. Then society met the issue squarely by declaring that the government alone possessed the power to compel the railroads of the country to conduct their business so as to furnish efficient and reasonably priced service.

While the regulation of railroads is the most outstanding example of the government's power in this respect, it has been effectively exerted against the trusts. And there is no reason to believe, should occasion arise, that the federal government would hesitate to exert its authority against any other monopolies. Because of past experiences and future possibilities, monopolists are wise to conduct their business somewhere near a competitive basis.