II. A neutral State is not bound to prevent such assistance being rendered by its subjects to either belligerent as is involved in, e.g. blockade-running or carriage of contraband; but merely to acquiesce in the loss and inconvenience which may in consequence be inflicted by the belligerents upon persons so acting. In order to explain this statement, it became necessary to say much as to the true character of "carriage of contraband" (although this topic is more specifically dealt with in the letters contained in Section 5), and to point out that such carriage is neither a breach of international law nor forbidden by the law of England. For the same reason, it seemed desirable to criticise some of the clauses now usually inserted in British Proclamations of Neutrality.
The view here maintained commended itself to the Institut de Droit International, at its Cambridge and Venice sessions, 1895, 1896, as against the efforts of MM Kleen and Brusa to impose on States a duty of preventing carriage of contraband by its subjects (_Annuaire_, t. xiv. p. 191, t. xv. p. 205). It has now received formal expression in The Hague Convention No. x. of 1907, Art. 7 of which lays down that "a neutral Power is _not_ bound to prevent the export or transit, for the use of either belligerent, of arms, ammunition, or, in general, of anything which could be of use to an army or fleet."
Sir,--As a good deal of discussion is evidently about to take place as to the articles which may be properly treated as contraband of war, and, in particular, as to coal being properly so treated, I venture to think that it may be desirable to reduce this topic (a sufficiently large one) to its true dimensions by distinguishing it from other topics with which it is too liable to be confused.
Articles are "contraband of war" which a belligerent is justified in intercepting while in course of carriage to his enemy, although such carriage is being effected by a neutral vessel. Whether any given article should be treated as contraband is, in the first instance, entirely a question for the belligerent Government and its Prize Court. A neutral Government has no right to complain, of hardships which may thus be incurred by vessels sailing under its flag, but is bound to acquiesce in the views maintained by the belligerent Government and its Courts, unless these views involve, in the language employed by Lord Granville in 1861, "a flagrant violation of international law." This is the beginning and end of the doctrine of contraband. A neutral Government has none other than this passive duty of acquiescence. Its neutrality would not be compromised by the shipment from its shores, and the carriage by its merchantmen, of any quantity of cannon, rifles, and gunpowder.