On Sept. 18, 1931, a small bomb exploded underneath a section of track on the South Manchuria Railroad. The Japanese Army, which under long-standing agreements policed the railroad, used this incident as a pretext for launching operations aimed at conquering all of Manchuria for Japan. The Chinese government, which had nominal sovereignty over the area, protested to the League of Nations. Some supporters of the principle of collective security saw an opportunity for the League to prove that it was capable of stopping an aggressor. The majority of member governments, however, did not, feeling that the fate of Manchuria was not of vital concern to them, or that the Japanese had some justice on their side, or that action by the League might harm moderates in Tokyo who were trying to hold the army in check. In the upshot the Council passed two resolutions, one on September 30 and the other on October 23, urging the Japanese to cease their military operations and enter into direct negotiations with China and appointing a special commission to investigate the situation and help the parties reach a settlement.
Paying little attention to the League’s advice, the Japanese continued their ,operations. When the Chinese organized a boycott of Japanese goods, they went even further. Reinforcing the garrison which they already maintained at Shanghai, in January 1932 they seized control of that city. By May they had been persuaded by League mediators to reach a truce agreement with the Chinese in Shanghai, from which their forces were gradually withdrawn. In the meantime, however, they had convened in Manchuria a rump assembly and had it proclaim the independence of the region, now to be called Manchukuo, on February 18. The new state, which came into existence officially on March 1, signed with Japan on September 15 a treaty making it a virtual ward of that country.
The first Western nation to show umbrage over these events was the United States. Despite its isolationism it had a long tradition of interest in the Far East. When the League Council convened to hear the Chinese protests, the American government sent an official observer to Geneva. The view in Washington at that time was that Western powers ought not to do anything that might aggravate the political situation in Tokyo, but Secretary of State Henry L. Stimson subsequently became convinced that there ought to be some general assertion of opposition to Japanese aggression.. Although himself in favor of threatening Japan with collective sanctions, he had to reckon with the stubborn pacifism of President Herbert Hoover. The most that he could do was, on Jan. 7, 1932, to dispatch a formal note to Tokyo, declaring that the United States would not recognize Japanese sovereignty over territory acquired by force. This formulation was termed variously the Stimson Doctrine and the Hoover Doctrine. Although one of the arguments used by opponents of League action had been the fact that the United States was not a member of the organization, the American initiative attracted little immediate support. When asked by Stimson to make a similar declaration, the British government declined. Not until after the evacuation of Shanghai did British statesmen even suggest that the League might adopt the Stimson Doctrine as its own.
The sessions of the League Assembly in the fall and winter of 1932-1933 were devoted largely to the Manchurian issue. The commission of inquiry, headed by the 2d earl of Lytton, made its report, stating that while the Japanese had possessed some grievances their action had been excessive, that the establishment of an independent Manchukuo had not been in accordance with the wishes of the people, and that Japanese forces ought to return the rail lines, restore the status quo ante bellum, and negotiate a new understanding about Manchuria with the Chinese. After prolonged debate the Assembly adopted on Feb. 24, 1933, a resolution refusing to recognize Manchukuo and calling on the Japanese to retire. The only result was to bring on March 27 the resignation (effective in two years’ time) of Japan from the League of Nations. The system of collective security created by the Paris peace treaties had been tested and been found wanting.