The general weaknesses of the League are illustrated by its specific failures.

Cieszyn

Rencana utama: History of Cieszyn and Tesin and Border conflicts between Poland and Czechoslovakia

Cieszyn (German Teschen, Czech Těšín) is a region between Poland and today's Czech Republic, important for its coal mines. Czechoslovakian troops moved to Cieszyn in 1919 to take over control of the region while Poland was defending itself from invasion of Bolshevik Russia. The League intervened, deciding that Poland should take control of most of the town, but that Czechoslovakia should take one of the town's suburbs, which contained the most valuable coal mines and the only railroad connecting Czech lands and Slovakia. The city was divided into Polish Cieszyn and Czech Český Těšín. Poland refused to accept this decision; although there was no further violence, the diplomatic dispute continued for another 20 years.

Vilna

After World War I, Poland and Lithuania both regained the independence that they had lost during the partitions of Poland in 1795. Though both countries shared centuries of common history in the Polish-Lithuanian Union and Polish-Lithuanian Commonwealth, rising Lithuanian nationalism prevented the recreation of the former federated state. The city of Vilna (Lithuanian Vilnius, Polish Wilno) was made the capital of Lithuania, despite being mainly Polish in ethnicity.

During the Polish-Soviet War in 1920, a Polish army took control of the city. Despite the Poles' claim to the city, the League chose to ask Poland to withdraw: the Poles did not. The city and its surroundings were proclaimed a separate state of Central Lithuania and on 20 February 1922 the local parliament passed the Unification Act and the city was incorporated into Poland as the capital of the Wilno Voivodship. Theoretically, British and French troops could have been asked to enforce the League's decision; however, France did not wish to antagonise Poland, which was seen as a possible ally in a future war against Germany, while the United Kingdom was not prepared to act alone. Both the United Kingdom and France also wished to have Poland as a 'buffer zone' between Europe and the possible threat from Communist Russia. Eventually, the League accepted Wilno as a Polish town on March 15 1923. Thus the Poles were able to keep it until Soviet invasion in 1939.

Lithuanian authorities declined to accept the Polish authority over Wilno and treated it as a constitutional capital. It wasn't until the 1938 ultimatum, when Lithuania resolved diplomatic relations with Poland and thus de facto accepted the borders of its neighbour.

Ruhr

Under the Treaty of Versailles, Germany had to pay reparations. They could pay in money or in goods at a set value; however, in 1922 Germany was not able to make its payment. The next year, France and Belgium chose to act upon this, and invaded the industrial heartland of Germany, the Ruhr, despite this being in direct contravention of the League's rules. With France being a major League member, and the United Kingdom hesitant to oppose its close ally, nothing was done in the League despite the clear breach of League rules. This set a significant precedent – the League rarely acted against major powers, and occasionally broke its own rules.

Corfu

One major boundary settlement that remained to be made after World War I was that between Greece and Albania. The Conference of Ambassadors, a de facto body of the League, was asked to settle the issue. The Council appointed Italian general Enrico Tellini to oversee this. While examining the Greek side of the border, Tellini and his staff were murdered. Italian leader Benito Mussolini was incensed, and demanded the Greeks pay reparations and execute the murderers. The Greeks, however, did not actually know who the murderers were.

On 31 August 1923, Italian forces occupied the island of Corfu, part of Greece, with fifteen people being killed. Initially, the League condemned Mussolini's invasion, but also recommended Greece pay compensation, to be held by the League until Tellini's killers were found. Mussolini, though he initially agreed to the League's terms, set about trying to change them. By working on the Conference of Ambassadors, he managed to make the League change its decision. Greece was forced to apologise and compensation was to be paid directly and immediately. Mussolini was able to leave Corfu in triumph. By bowing to the pressure of a large country, the League again set a dangerous and damaging example. This was one of the league's major failures.

Krisis Manchuria

The Manchuria Crisis was one of the League's major setbacks and acted as the catalyst for Japan's withdrawal from the organisation. In the Mukden Incident, the Japanese held control of the South Manchurian Railway in the Chinese region of Manchuria. They claimed that Chinese soldiers had sabotaged the railway, which was a major trade route between the two countries, on 18 September 1931. (In fact, the sabotage had been committed by Japanese Army personnel bent on establishing a pretext for conquest.) In retaliation, the Japanese army, acting contrary to the civilian government's orders, occupied the entire province of Manchuria, which they named Manchukuo. In 1932, Japanese air and sea forces bombarded the Chinese city of Shanghai and a short war broke out.

The Chinese government asked the League for help, but the long voyage around the world for League officials to investigate the matter themselves delayed matters. When they arrived, the officials were confronted with Chinese assertions that the Japanese had invaded unlawfully, while the Japanese claimed they were acting to keep peace in the area. Despite Japan's high standing in the League, the Lytton Report declared Japan to be in the wrong and demanded Manchuria be returned to the Chinese. However, before the report was voted upon by the Assembly, Japan announced intentions to invade more of China. When the report passed 42-1 in the Assembly (only Japan voted against), Japan left the League. Economic sanctions were powerless, since Japan's major trading partner was the U.S., which was not a member of the League and declined to cooperate with it out of fear of war. The United Kingdom, concerned about the security of its large commercial interests in China as well as its Asian colonies, was reluctant to anger Japan over a region that was not central to its own interests. Once again, the League bowed to the more powerful, and showed its weakness.

Perang Chaco

The League failed to prevent the Chaco War between Bolivia and Paraguay in 1932 over the arid Chaco Boreal region of South America. Although the region was sparsely populated, it gave control of the Paraguay River which would have given one of the two landlocked countries access to the Atlantic Ocean, and there was also speculation, later proved incorrect, that the Chaco would be a rich source of petroleum. Border skirmishes throughout the late 1920s culminated in an all-out war in 1932, when the Bolivian army, following the orders of President Daniel Salamanca Urey, attacked a Paraguayan garrison at Vanguardia. Paraguay appealed to the League of Nations, but the League did not take action when the Pan-American conference offered to mediate instead.

The war was a disaster for both sides, causing 100,000 casualties and bringing both countries to the brink of economic disaster. By the time a ceasefire was negotiated on 12 June 1935, Paraguay had seized control over most of the region. This was recognized in a 1938 truce by which Paraguay was awarded three-quarters of the Chaco Boreal.

Perang Saudara Sepanyol

Pada 17 Julai 1936, konflik bersenjata meletus di antara Republikan (kerajaan sayap kiri Sepanyol) dan Nasionalis (pemberontak sayap kanan, kebanyakkannya pegawai Tentera Darat Sepanyol). Alvarez del Vayo, Menteri Luar Sepanyol, merayu kepada Liga Bangsa pada bulan September 1936 mendapatkan persenjataan bagi mempertahankan integriti wilayah dan kemerdekaan politik Itali. Bagaimanapun, Liga Bangsa tidak dapat campur tangan dalam Perang Saudara Sepanyol mahupun menghalang penglibatan luar dalam konflik ini. Hitler dan Mussolini terus menerus membantu pemberontak Nasionalis yang diketuai oleh Jeneral Franco, manakala Kesatuan Soviet pula membantu pengikut setia Sepanyol. Liga Bangsa telah mencuba untuk menghalang penglibatan sukarela antarabangsa.

Pencerobohan Abyssinia Itali

Antara kejadian yang paling terkenal berlaku pada bulan Oktober 1935, apabila Benito Mussolini mengarahkan Jeneral Pietro Badoglio dan 400,000 tentera untuk menceroboh Abyssinia (Habsyah). Tentera Darat Itali yang moden dengan mudahnya mengalahkan pasukan Abyssinia yang miskin dan memiliki persenjataan lemah, dan menawan Addis Ababa pada bulan Mei 1936, memaksa Maharaja Haile Selassie untuk melarikan diri. Itali telah menggunakan senjata kimia (gas mustard) dalam menentang Abyssinia.

Liga Bangsa telah mengutuk serangan Itali dan mengenakan sekatan ekonomi pada bulan November 1935, bagaimanapun sekatan ini tidak berkesan. Perdana Menteri Britain, Stanley Baldwin menyatakan, perkara ini terjadi kerana tiada seorangpun yang memiliki pasukan tentera untuk bertahan daripada serangan Itali. Pada 9 Oktober 1935, Amerika Syarikat (bukan ahli Liga Bangsa) enggan bekerjasama dengan tindakan Liga Bangsa. It had embargoed exports of arms and war material to either combatant (in accordance with its new Neutrality Act) on 5 October and later (29 February 1936) endeavored (with uncertain success) to limit exports of oil and other materials to normal peacetime levels. The League sanctions were lifted on 4 July 1936, but by that point they were a dead letter in any event.

As was the case with Manchuria, the vigor of the major powers in responding to the crisis in Abyssinia was tempered by their perception that the fate of this poor and far-off country, inhabited by non-Europeans, was not a central interest of theirs.

Axis re-armament

The League was powerless and mostly silent in the face of major events leading to World War II such as Hitler's re-militarisation of the Rhineland, occupation of the Sudetenland and annexation of Austria. As with Japan, both Germany in 1933 – using the failure of the World Disarmament Conference to agree to arms parity between France and Germany as a pretext – and Italy in 1937 simply withdrew from the League rather than submit to its judgment. The League commissioner in Danzig was unable to deal with German claims on the city, a significant contributing factor in the outbreak of World War II in 1939. The final significant act of the League was to expel the Soviet Union in December 1939 after it invaded Finland.