On the sea the Germans had abandoned hope of victory. The balance of power in our favour, which had been insufficient to relieve Jellicoe of considerable anxiety, began to increase rapidly with the completion of the Queen Elizabeth class in April; and Germany turned her anticipatory gaze towards her submarines. Just as Napoleon's efforts by means of the Berlin and Milan decrees to ruin us by war on commerce came after the final collapse of his naval ambitions at Trafalgar, so Germany's submarine campaign followed upon her recognition of the hopelessness of her naval situation. On 18 February she proclaimed the waters round the British Isles a war zone in which enemy merchantmen would, and neutrals might, be sunk by submarines irrespective of the risks to non-combatants and neutrals. This was a flagrant violation of the rules of international law which safeguarded the shipping of neutrals, and only sanctioned the condemnation of contraband goods in prize courts, and the destruction of enemy vessels when they could not be taken into port and provision had been made for the safety of their crews and passengers. The German submarines were not in a position to guarantee any of these conditions; and trading on the legal maximum that no one can be required to do what is impossible, the Germans claimed immunity from these obligations. To this the British Government replied on 1 March with a blockade which was more humane and more effective, but none the less involved an autocratic extension of belligerent rights. All oversea trade with Germany was to be as far as possible intercepted; goods, whether contraband or not, were at least to be detained; and the right of search was to be rendered more secure by being exercised in British ports, to which neutral ships were brought, instead of on the high seas amid the danger of submarine attack. These measures inflicted no loss of life and no loss of property that was not contraband. But they made havoc with the ideas that neutrals were entitled to trade with both belligerents, and that neither belligerent could intercept commerce which did not directly serve for military purposes. It was not, for instance, a breach of neutrality to sell munitions to a belligerent, though belligerents were entitled to seize them if they could; and we ourselves bought vast quantities from the United States. America was, however, deeply attached to that "freedom of the seas" which enabled neutrals to sell, without interference, goods which were not contraband, to either belligerent; and our extension of contraband to cover food supplies gave deep offence. The difficulty arose not only from the inevitable tendency of law to disappear amid the clash of arms, but from the modern absorption of all energies, civilian as well as military, in the warlike operations of the State. The food of civilians making munitions became a vital element in the conduct of war, and the distinction between civil and military purposes was lost