There is no objection to predicating the existence of this double allegiance, for, despite the fact that modern sovereignty is generally spoken of as territorial, it is, in fact, personal, and imports a personal relationship between the sovereign political person - the State - and its political inferiors, its subjects. Sovereignty in truth is a purely legal concept and exists only within the field of constitutional law. International relations, the relations between States, are not legal in character, and international laws, so-called, are not laws at all in a strict positive sense. They are not commands from a legal superior to a legal inferior, but are regulations governing the conduct of political equals. Within this general international field the authority or jurisdiction of governments is strictly territorial - over each territorial district there is a particular de facto government recognized by the various States to have a right based upon actual power, to exercise political control, and, correspondingly, is held by them responsible for whatever occurs within such districts. Internationally speaking, therefore, jurisdiction is territorial and exclusive. Over any given territory, one, and only one, governing body is recognized to have legitimate authority. But sovereignty, denoting, as said, legal supremacy, a personal relationship, as predicated upon a legal subjection or allegiance of individuals to a legal superior, is not territorial; and there is thus no inherent difficulty in a sovereign claiming legal authority over individuals located outside of the limits of the territory conceded by other nations to belong to it; or of two or more States claiming at the same time, under the operation of their respective municipal laws, the allegiance of the same individual, as for instance, as we shall presently see, when one State naturalizes the subject of a State whose municipal law does not recognize the right of expatriation.

4 Webster's Works, VI, 526.

5 United States v. Carlisle, 16 Wall. 147; 21 L. ed. 426; United States v. Wong Kim Ark, 169 U. S. 649; 18 Sup. Ct. Rep. 456; 42 L. ed. 890.

From the viewpoint of international relations, as we have just seen, the law of one State is not permitted by other States to operate outside of the territorial limits of the State which promulgates it, and, therefore, though claiming a legal authority over an individual outside of such limits, a State will not be permitted by other States to exercise it against the consent of the State within whose limits the individual is situated. But that does not render impossible the existence of or invalidate such a claim, for when, if ever, such an individual is apprehended within the territory of the State claiming authority over him he may be held responsible for acts committed while abroad. And also, as still more plainly showing the personal and non-territorial character of allegiance and sovereignty is the principle universally recognized both in municipal and international law, that a citizen of a State is in many cases entitled to the protection of that State while abroad. Thus he does not in any way lose his citizenship ly departing from the territorial limits of the State of which he is a member, nor does he escape from beneath its law or cease to be entitled to its protection.