court, such as we have here, as it was held to be in the cases cited 33 in which claims for damages were based upon acts done in a foreign country, for it rests at last upon the highest considerations of international comity and expediency. To permit the validity of the acts of one friendly State to be re-examined and perhaps condemned by the courts of another would very certainly imperil the amicable relations between Governments and vex the peace of nations."

Aerial Jurisdiction. With the development of the art of navigating the air the extent to which it will be internationally, as well as nationally, expedient that a State should have jurisdiction over the air above its land area is a matter which as yet has not received clear determination. It does not appear, however, that the introduction of this new element into the political problem will make it necessary to change accepted fundamental notions of the State's jurisdictional powers. Before the Great War international conferences assembled at Paris and Verona with a view to seeing if all the States of the world, or a major part of them, might not come to some general agreement upon this subject and thus avoid occasions for dispute. The matter was also considered at various meetings of the Institute of International Law. At the Paris Peace Conference, in 1919, aerial jurisdiction was discussed and a convention drawn up and signed, October 13, 1919, to which the five principal Allied Powers were named as parties. The rules of this agreement apply only in times of peace, and, therefore, do not restrain the action of the parties to it in times of war either as neutrals or belligerents. But the convention does explicitly recognize, as a fundamental proposition,

250.

Williams v. Bruffy, 96 U. S. 176; Underhill v. Hernandez, 168 U. S.

that each State has complete and exclusive jurisdiction over the air space above its land area and territorial waters.34

Garner 35 classifies as follows the various international law writers as regards the doctrines recommended by them for adoption by the nations of the world:

1. "Those who assert that the air is or should be absolutely free for purposes of aerial navigation by aviators of all countries."

2. "Those who assert the general principle of the freedom of the air subject to a certain right of control by the subjacent State over the superincumbent atmosphere up to a certain height. This area they call the 'territorial zone.""

3. "Those who advocate the general principle of the freedom of the air but allow the underlying State to exercise control over it up to an indefinite height for purposes of self-protection and preservation.”

4. "Those who contend for the absolute sovereignty of the underlying State for any and all purposes over the aerial domain above the territory."

5. "Those who contend for the principle of absolute sovereignty subject to the right of free passage. This is the view embodied in the convention relating to international air navigation, agreed to by the representatives of the Allied and Associated Powers at the Peace Conference in 1919." 36

The rule adopted by the Institute of International Law

For a reference to the leading discussions of this topic see the third edition (1920) of Oppenheim's International Law, vol. I, pp. 352 et sec. Also see the article of Professor G. G. Wilson, "Aerial Jurisdiction" in the American Political Science Review, vol. V, p. 71 (May, 1911); G. G. Bogert, "Problems in Aviation Law" in the Cornell Law Quarterly, vol. VI, p. 271; and Garner, International Law and the World War, vol. I, p. 478, and numerous authorities there cited.

35

Op. cit., vol. I, p. 479.

Garner lists the names of writers giving, respectively, their adherence to the enumerated doctrines.

in 1906 declares the air domain to be free in war as in peace, subject only to the right of underlying States to take appropriate measures to protect persons and property upon their respective soils.

Radio. The rapid development of radio communication throughout the world has rendered still more necessary an agreement of the nations upon some generally binding rules as to the use of the air for purposes of wireless operations, whether in times of peace or of war.3

37

See the testimony of O. D. Young, of the Radio Corporation of America, before the Committee on Interstate Commerce of the United States Senate, 66th Congress, third session. (U. S. Government Printing Office, 1921.)

CHAPTER XIX

PERSONAL JURISDICTION

Citizenship. The juristic conception of the State which has been outlined emphasizes the fact that citizenship is a status imposed by the State upon such individuals as it desires to draw beneath its authority, and is not in any sense a status created by or dependent upon the consent of the citizens themselves.1 From this it logically follows that each State is universally recognized to have the power of determining for itself who shall be deemed its subjects—whether according to the rule of jus soli or jus sanguinis, or of both; who may become its naturalized citizens, and under what conditions; what rights shall be granted to aliens, domiciled or undomiciled; who may enter or remain within its territorial borders; and whether or not the right of expatriation shall be recognized, and, if recognized, upon what conditions.

It has already been seen that it is a premise of public law that a sovereign political power has the legal authority to extend its political control over such territory and such individuals as it may see fit, and that it would thus be conceivably possible for any given State to extend its jurisdiction over all persons whomsoever. As a matter of practical fact, however, no State attempts to exercise this plenitudo potestatis and hence arises a distinction between those who are regarded as owing an allegiance to

1

Credit is due to Professor R. T. Crane, now of the University of Michigan, for the clearness with which he pointed out that a citizen's allegiance to his State is in no wise to be construed as a contract between himself and the State. See Johns Hopkins University Studies in Historical and Political Science, Series XXV, pp. 329-330.

a given territory and those who do not. Those who are deemed to owe this allegiance are divisible into two classes. The first of these classes includes those who are deemed citizens or subjects, and who have obtained or have had imposed upon them their status as such by reason of the nationality of their parents or birth within the territorial jurisdiction of the State, or have been formally assimilated to these by adoption by the State by a process that is called "naturalization." Ordinarily, of course, this process of naturalization is one which is initiated and desired by the one thus seeking a new citizenship, but not infrequently this new citizenship is imposed without the desire or consent of the persons affected, as for example, when, by treaty or statute, the inhabitants of an annexed district are naturalized en bloc.

Never is it the case that one may claim citizenship as a legal right, nor may it be surrendered or in any way gotten rid of, save with the consent of the State to which it is due. This is a doctrine of public law enforced by all sovereign States.

The allegiance of citizens or subjects is thus, so far as the control over it by themselves is concerned, permanent in character, and independent of the place where they may happen to be. This legal control which a State may exercise over its own citizens whether within or without its own territorial limits has already been adverted to.

Furthermore, it is within the legal power and discretion of every State to group its own citizens into various. classes and to award to the members of each special class such special public and private rights and duties as it may judge best. This, however, is a detail of a State's constitutional jurisprudence which has no bearing upon the essential nature of citizenship or allegiance. And equally immaterial upon this point is the question whether a State founds the status of citizenship upon the