our sentiments as well as upon every transaction that might be construed as a preference of one party to the struggle before another." As a neutral power, the U.S. insisted on its right to trade with both sides. However the powerful British Royal Navy imposed a blockade of Germany. To appease Washington, London agreed to continue purchasing certain major American commodities such as cotton at pre-war prices, and in the event an American merchant vessel was caught with contraband, the Royal Navy was under orders to buy the entire cargo and release the vessel. Wilson passively accepted this situation. In response to the British blockade, Germany launched a submarine campaign against merchant vessels in the seas surrounding the British Isles. In early 1915, the Germans sank three American ships; Wilson took the view, based on some reasonable evidence, that these incidents were accidental, and a settlement of claims could be postponed until the end of the war. In May 1915, a German submarine torpedoed the British ocean liner RMS Lusitania, killing 1,198 passengers, including 128 American citizens. Wilson publicly responded by saying, "there is such a thing as a man being too proud to fight. There is such a thing as a nation being so right that it does not need to convince others by force that it is right". Wilson demanded that the German government "take immediate steps to prevent the recurrence" of incidents like the sinking of the Lusitania. In response, Bryan, who believed that Wilson had placed the defense of American trade rights above neutrality, resigned from the Cabinet. In March 1916, the SS Sussex, an unarmed ferry under the French flag, was torpedoed in the English Channel and four Americans were counted among the dead. Wilson extracted from Germany a pledge to constrain submarine warfare to the rules of cruiser warfare, which represented a major diplomatic concession. Interventionists, led by Theodore Roosevelt, wanted war with Germany and attacked Wilson's refusal to build up the army in anticipation of war. After the sinking of the Lusitania and the resignation of Bryan, Wilson publicly committed himself to what became known as the "preparedness movement", and began to build up the army and the navy. In June 1916, Congress passed the National Defense Act of 1916, which established the Reserve Officers' Training Corps and expanded the National Guard. Later in the year, Congress passed the Naval Act of 1916,