On June 22 of this year important amendments to the Netherlands Constitution concerning the administration of foreign affairs came into force. As those amendments will not only be of interest to students of Netherlands constitutional law but also to those who are interested in the problem of the relationship between international and municipal law and modern tendencies in national constitutions in this respect, it might be useful to give a brief survey of these amendments and their background.

Every state has complete and exclusive sovereignty over the airspace above its territory. Consequently, no aircraft is normally entitled to enter the airspace above the territory of a foreign state without the latter’s permission Does this principle—very firmly established in international law since World War I—mean that any aircraft entering without such permission 1 is completely at the mercy of the territorial sovereign ? Or does international law impose some restraints upon the latter in this matter?

The war crimes trials following the second World War and the Geneva Conventions of 1949 have posed a question about war reprisals which is likely to be important in any future war and which has immediate practical significance in the current wars in Asia. On the one hand, the trials have transformed the previously sketchy rules on reprisals into a more comprehensive and elaborate system of control. On the other hand, the Geneva Conventions have provided for almost the complete abolition of reprisals in the very area for which the rules of control were formulated. Moreover, the conventions remain unratified by many of the major Powers, of which at least one has already demonstrated its inability to observe the abolition of reprisals. The core of the problem concerns reprisals against civilian persons in occupied territories, for this was by far the most significant point in the trials on reprisals and was the subject of the most outstanding innovation introduced by the Geneva Conventions. Nevertheless, the issues raised by the contradiction between the trials and the conventions cannot properly be discussed without reference to the general theory of war reprisals.

Expropriation of property belonging to aliens in foreign countries was unusual prior to World War I. Occasional cases could be found, but such expropriation was always restricted to one or a few owners of property who, for various reasons, came into conflict with a foreign government. Wholesale expropriation of foreign-owned property began on a moderate scale in Mexico in 1915, and was later expanded in that country. Expropriation of all kinds of property, including foreign property, was introduced by Soviet Russia after the 1917 revolution. After World War I some Eastern European countries, such as Poland, Rumania, Czechoslovakia, and Yugoslavia, began to expropriate the large agrarian estates of the former German, Austrian, and Hungarian nobility and other rich landowners. These expropriations were, by the terms of the agrarian reform laws, based upon compensation to be paid by the respective states.