Protectorate of the petty Arab chiefships on the southern shore of the Persian Gulf, established in order to prevent slave-raiding on the adjoining seas. The third case is the anomalous and unprecedented form of Protectorate declared by the United States of America in the extreme assertion of the Monroe doctrine over the Latin States of Central and Southern America. This Protectorate appears to involve a territorial guarantee of the States in question against any European Power; but what measure of internal control or interference it may be held to justify, no man can say.
Protectorates shade away by imperceptible degrees into the diplomatic concept now popularly known as Spheres of Influence. When first this phrase was employed in the language of diplomacy I do not know, but I doubt a more momentous early use of it can be traced than that in the assurance first given by Count Gortchakoff to Lord Clarendon in 1869, and often since repeated, that Afghanistan lay 'completely outside the sphere within which Russia might be called upon to exercise her influence'. Since those days Spheres of Influence have become, notably in Africa, though scarcely less in Asia, one of the recognized means of extending a Frontier or of pegging out a potential claim. A Sphere of Influence is a less developed form than a Protectorate, but it is more developed than a Sphere of Interest. It implies a stage at which no exterior Power but one may assert itself in the territory so described, but in which the degree of responsibility assumed by the latter may vary greatly with the needs or temptations of the case. The native Government is as a rule left undisturbed; indeed its unabated sovereignty is sometimes specifically reaffirmed; but commercial exploitation and political
