It is such agreements as these that are referred to in Article 9 of the Protocol as those "already existing under the terms of certain treaties." It is these zones, and others which may be established by consent of the neighboring States, which, according to Article 9, may be placed under a system of supervision by the League, either temporary or permanent. Obviously, any such supervision would come about by means of the voluntary agreement of the States concerned; and, in view of the fact that the Protocol makes a violation of a demilitarized zone the equivalent of a resort to war (Article 10), supervision by the League of the carrying out of these essential agreements would seem to be highly desirable.
Indeed, it may be said here that it will almost certainly be found that a system of international inspection will inevitably be a part of agreements for the reduction and limitation of armaments. A system of general international inspection was suggested as one of the parts of the so-called American Plan,[[4]] and the proposal for a system of supervision of demilitarized zones under the League of Nations is a part of that general idea.
I do not think it should be lost sight of that the thought of certain places where violence is forbidden has roots which go far back in human history. The idea of "sanctuary" is as old as any records that we have; and, if it be thought that I am going very far afield in speaking of sanctuary, I mention that the legal development of this general notion is a very early development. At least as long ago as Anglo-Saxon law in England, it was a peculiarly heinous offence to commit a crime on the King's Highway. It was a much more serious matter to break the peace there than elsewhere, because it was a breach of the King's peace; and this notion of the King's peace is said by high authority to be as old as the Salic Law.
We have heard much in the past of strategic frontiers. A great deal of ability and learning have been devoted toward the problem of making frontiers available for attack or for defence. It is perhaps true, as some critics appear to think, that the development of war in the air and of chemical warfare has made questions of strategic frontiers in general less important than heretofore. Perhaps that is so. I suggest, however, that even if it is so, that same ability and learning may be able to find in a combination of the ideas of demilitarized zones and international supervision a real solution of the problems arising from these new methods and discoveries; and, as I have pointed out, there is a very ancient human feeling behind this whole idea of peaceful places, on which popular support for such a programme may be based.
[[1]] Articles 42 to 44.
[[2]] A. J. I. L. Supplement 1923, Vol. XVII, p. 1.