312 HARVARD LAW REVIEW In the first place, the "police po-vyer," as referred to in the de- cisions, seems to be used in two ways: usually as referring to laws for the promotion of the public health, safety, And morals, but sometimes and less frequently, as referring to laws intended more generally for the public welfare. But, as Chief Justice Taney long ago pointed out,^^ practically all laws are police laws in this sense. That the "police power" in its more proper and Hmited sense is an inexact description of the rate-making power would seem to result from the following considerations: (a) In the first place it is well settled that the state police power cannot be bargained away, and yet it is equally well settled that the state may make a binding contract with a public utihty which will preclude it, for a substantial period of time, from regulating the rates of that utihty.^ (b) In the second place, the rate-regulating power is subject to the limitation that it may not be so exercised as to deny the public utility a reasonable return on the fair value of the property which it devotes to the public service; but the poHce power, in its true sense, is not subject to any such restriction, since it is well settled that it is permissible to require uncompensated obedience to a law which is essentially one of poHce. Both of these elementary prin- ciples are violated if we treat the rate-regulating power as a part of the state's police power. A true classification of the power to regulate rates, etc., would assimilate it to the power of eminent domain. The state requires a given service and fixes the price at which it shall be rendered.^ Just as the taking of the railroads by the government is a striking illustration of the exercise of this power, although it constitutes the taking of a limited interest or use only, so the taking of an even more limited use of the property, as for example, the requiring of the furnishing of a freight car to be used for the transportation of 544 (1892); German Alliance Insurance Co. v. Kansas, 233 U. S. 389 (1914); Puget Sound Traction Co. v. RejTiolds, 244 U. S. 574, 578, 579 (191 7). 2^ License Cases, 5 How. (U. S.) 504, 582-83 (1847). ^ Detroit v. Detroit Citizens' Street Ry., 184 U. S. 368 (1902); Cleveland v. Cleve- land City Ry. Co., 194 U. S. 517 (1904); Minneapolis v. Street Ry. Co., 215 U. S. 417 (1910). ^ It is true that prices may sometimes be regxdated, although there is no legal obligation to sell or render service; but it is not believed that this changes the essential situation since in the majority of instances there is a practical compulsion.
