In the early 1930s, the League of Nations was powerless to do much of anything regarding the Japanese invasion of Manchuria. After the Lytton Commission was sent to examine the situation and reported back the evidence that Japan was the wrongful aggressor against the Chinese, the League's response was one of strong but impotent disapproval: all except Japan voted for Japan to withdraw its troops from Manchuria. Japan's response was simply to leave the League of Nations altogether and continue to do as it pleased. Germany and Italy would follow in Japan's steps years down the road.

By the time Japan began its invasion of Manchuria, the power of the League of Nations to keep world peace was already in doubt. Its critics, which had included Italian fascist leader Benito Mussolini, had claimed that the League would be powerless to stop any aggressive nation from conquest because it had no military force to back up its peacekeeping aims. The League could clamor for peace all it wanted, but if a powerful enough country like Japan decided it wanted to pursue territorial conquest or commit aggressive acts against its neighbors, then there was nothing the League could do to make them stop.

The League of Nations was established after World War I to try to build and maintain a more peaceful world following the immense tragedy of that war—a war which many believed could have been prevented had more diplomatic avenues been open in 1914. The League was an attempt to foster an attitude of internationalism and cooperation.

However, like the Articles of Confederation (the earliest document that joined the United States together), the League of Nations was fatally flawed in being too weak to be effective. Unlike the later United Nations, there was no peace-keeping aspect to the League that could have given China military aid against Japan.

Japan violated the League of Nations in 1931 when it invaded Manchuria. The League's chief weapon, economic sanctions, was ineffective. Japan, ruled by a reactionary Emperor under the influence of generals with expansionist ambitions, simply ignored the League's demand that it leave China and instead withdrew from the League. This paved the way for other militaristic dictatorships, such as Germany and Italy, to also leave the League in the 1930s.

Nationalism won out over internationalism, and an unchecked Japan perpetrated atrocities on the badly weakened Manchuria. The lesson of Manchuria was that international organizations needed military power to be effective.

The Japanese invasion of Manchuria, like the Italian invasion of Abyssinia, showed the League of Nations to be a paper tiger when it came to dealing with acts of illegal aggression on the international stage. In both cases, a dictatorship with dreams of empire had invaded a foreign land, and in both cases, the League had been importent in preventing these dictatorships from getting what they wanted.

In the case of the Japanese invasion of Manchuria in 1932, the League responded in the weakest possible way, by sending a fact-finding delegation to China under the leadership of Lord Lytton, a British politician and colonial administrator. The Lytton Commission, as it was called, gathered evidence and in its final report apportioned blame for the invasion on both sides. Yet the lion's share of blame was accrued to Imperial Japan, which was ordered by the League of Nations to leave Manchuria forthwith.

However, as the League lacked any military power to back up its orders, the Japanese completely ignored the ultimatum. Not only did they remain in China, but they withdrew from the League altogether, an action that would be followed by Mussolini in 1937 after the League imposed economic sanctions on Fascist Italy for its invasion of Abyssinia.

The League of Nations responded to Japan's invasion of Manchuria by setting up the Lytton Commission to investigate the Japanese invasion of Manchuria. Its report assigned blame both to Chinese nationalism and to Japanese aggression. At the same time, the League of Nations refused to give the puppet-state Japan set up in Manchuria, Manchuko, official recognition. Japan's response was to leave the League of Nations and continue the course it had started.

Ultimately, the League of Nations' response here is consistent with more long-standing themes relating to the lead-up of World War II. Consider Japan's later invasion of China in 1937, or Italy's invasion of Ethiopia (1935), or the aggression of Nazi Germany, beginning with its occupation of the Rhineland (a demilitarized zone under the terms of the Treaty of Versailles) and leading up to its invasion of Poland (at which point the UK and France responded with declarations of war). Across so much of this history, one can observe in the great western democracies a general sense of paralysis in the face of militaristic aggression.

In September 1931, Japan used railway explosion as an excuse to invade China. By February 1932, Japan had conquered the whole area and established their own government there named Manchukuo. Suffering enormously from Japan’s military attack, China appealed to the League of Nations for help. In response to the Chinese claims, the League sent a commission led by a British official called Lytton to investigate the issue. In October 1932, a year after Japan’s invasion, the Lytton Report was published and Japan was found guilty. In February 1933, the League held a special assembly where all its members except Japan voted that the Japanese army should leave China. Japan refused to do so. It left the League and further expanded its aggressive movements. Then the League couldn’t do anything about it because main League members wanted to maintain Japan as a normal trading partner (so economic sanctions wouldn’t work), and no country wanted a war with Japan.