Inter-War Diplomacy


The major powers had different aims in 1919 for the post-war world.

  1. USA – The republicans defeated Woodrow Wilson in the 1920 presidential election, and they wanted isolation from European affairs.
  2. France – France still wanted security from the possibility of a third German attack. To do this she had two policies:

    Encirclement – She tried to surround Germany with countries who were friendlier to France, Yugoslavia, Czechoslovakia, Rumania and Poland (The Little Entente)

    France rearmed herself and strengthen her Rhineland border with Germany, by building the Maginot Line (1929-34)

  3. Britain wanted to recover her wealth and power via trade.
  4. Germany – The Weimar government wanted recovery in every sense: military, economic, political and diplomatic. In order for Germany to achieve any of these, she would have to break the Treaty of Versailles (28th June 1919).

Note: Britain and Germany had one thing in common – the need to recover via trade.

Improvement and Decline in International Relations (1920-39)


There was an improvement in international relations in the 1920s, mainly due to the work of three foreign ministers: Austen Chamberlain, Briand and Stresemann (Britain, France and Germany)


Relations between the powers deteriorated in the 1930s,l especially after 1929, after the Wall Street Crash (29th October) when the major powers’ economies declined, leading to a depression. As a result of the depression, extremist groups (Communists and Fascists) became popular (flourished). The aggressive policies of the Fascists (Germany, Italy and Japan) resulted in the Second World War.)

Inter-War Diplomacy: Improved Relations 1921-29

A. Washington Naval Treaties (1921-2)

Though following a policy of isolation the USA hosted these talks about naval disarmament, especially the balance of power in the Pacific.

Agreements Reached

  1. GB, USA, France & Japan agreed to respect each other’s Pacific possessions & guarantee China’s independence.
  2. Japan would restore Kias-Chow & Shantung to China. Japan to withdraw from Siberia, in Russia.
  3. There would be a ten year stoppage in the building of capital ships (more than 10,000 tons with guns larger than 8"). A ratio of USA:5, GB:5, Japan:3, France:1.75 and Italy:1.75 was to be maintained in the building of capital ships.


  1. Lessened possibility of naval war in the Far East where Japan & USSR had ideas about expanding into China.
  2. The alliance of First World War victors was reaffirmed, despite USA’s isolation policy.
  3. Though better international relations resulted, the USSR was not invited to the talks, despite her extensive Far Eastern interests. (USSR was, as yet, not recognised.)
  4. Treaty of Rapallo (April 1922) – Signed, 2 months after the Washington Treaty, by Germany and Soviet Russia. They said they would not attack each other and trade links were opened. Both powers were no longed isolated.

B. The Locarno Pacts, 1925

Britain, France & Germany agreed to meet in Switzerland, at Locarno, in 1925.


  1. Germany accepted her frontiers with France and Belgium, & agreed not to change them.
  2. Germany agreed not to alter her borders with Poland or Czechoslovakia without discussion with France and her Little Entente partners.


  1. Relations between France and Germany improved because France felt more secure and Germany realised there was some hope of regaining lands on her eastern borders.
  2. Germany joined the League of Nations as a permanent member of the Council in 1926.

C. Kellogg-Briand Pact (Pact of Paris) 1928

In 1926 Germany signed a Treaty of Neutrality with the USSR. (Renewed Rapallo of 1922.) This worried the French. In April 1927 Briand appealed to the US Secretary of State, F.B. Kellogg for assistance. A nine power conference met in Paris in August 1928 and eventually 65 nations signed a pact that outlawed war unless a nation acted in self-defence.


  1. US involvement reassured France and America’s other European allies.
  2. USSR signed the Pact and marks some recognition of Communist Russia by other powers.
  3. Germany signed the Pact and this allayed French suspicions of Germany’s aggression.
  4. This Pact was later viewed as being of good intent, but having no practical means of preventing war.

D. Changes to Reparations

J.M.Keynes had wanted that £6,600 million was too much to expect from Germany in reparations. Two plans, in 1924 and 1929, gave Germany assistance from the US.

a. Dawes Plan 1924

Germany fell behind in reparation payments to France, so in January 1923, France occupied the Ruhr valley (on the Franco-Germany Rhineland border). France’s intention was to take reparations in the form of coal. France only withdrew her troops after the Dawes Plan was drawn up. Germany still had the same amount to pay in reparations, but received a loan of 40 million and payments were phased in steps: 50 million in the first year, building up to 125 million in the 5th year.

  1. The Ruhr was evacuated in July 1925.
  2. Germany was treated as an equal for the first time, and this paved the way for Locarno (1925) and Germany’s entry to the League (1926)
  3. Germany’s economy improved under Stresemann (died 1929)

Young Plan 1929

Stresemann appealed to the USA for further assistance in paying reparations (to update the Dawes Plan). The Young committee reduced Germany’s liability to 2,000 million (about 1/3 of the original sum), to be paid over 59 years (i.e. Until 1988). It was to start in May 1930.

  1. Stresemann’s status as an international statesman grew, as did his popularity at home.
  2. The realistic sum to be paid by Germany promised well for future relations between Germany, France and Britain.

NB. The Young Plan collapsed because in October 1929, the Wall Street Crash occurred in America, and this financial crisis spread to Germany, and then other European powers. Germany could not afford to pay reparations 1931-2, and Hitler refused to pay anything after 1933.


Improvements in international relations in 1920s, A-D above, were the result of ‘power diplomacy’ and NOT the work of the League of Nations whose main aim was to keep peace.

Deterioration in Relations (1929-39)

In the 1930s relations between the powers deteriorated.

1929 Stresemann died and Briand and Chamberlain were out of office.

October 1929, Wall Street Crash, led to a depression in Europe and extremist political groups (Fascist, Nazis) grew in popularity. Mussolini in Italy and Hitler in Germany offered economic growth to their ‘depressed’ peoples and their aggressive foreign policies led to the Second World War (1939-45).

In the 1930s neither power diplomacy, nor the League of Nations, could prevent war.

The League of Nations


The idea of international co-operation was not a new one in 1919. There had been earlier attempts, for example:

The last of Wilson’s fourteen points said that a League of Nations should be set up, to keep peace after 1919. To ensure that it was established, Wilson insisted that the League of Nations should be written into the Treaty of Versailles (28th June 1919).


  1. To keep peace
  2. To improve living conditions of men and women world-wide


The League first met in 1920, in January, and each state had to take an oath (covenant) to say they would abide by the League’s rules for international law and order. The diagram below outlines the organisational structure of the League.

Organisational structure of the League of Nations


In the autumn of each year, each state would send up to three delegates to the Geneva assembly to discuss world problems. Each country had one vote, and a unanimous vote was needed to decide action. As unanimity was never reached, resolutions were passed onto the council.


The great powers (Britain, France, Italy and Japan) of 1920 sat permanently on the council, with smaller nations who observed. They met three or four times a year, and at times of crisis. By a unanimous vote they could levy three sanctions against a nation who broke peace:

  1. Moral sanction – A polite warning
  2. Economic sanction – The League stopped trading with the offender
  3. Military sanction – As a last resort the League would impose its will by force

No sanction could be used if a nation used its veto. The idea was that collective action would produce collective security, and thereby peace. (United we stand, divided we fall) The League’s responses were long-winded.

The Court of Justice

Set up in 1899, at The Hague, in Holland, this department dealt with legal disputes between nations.

International Labour Organisation (ILO)

Its first chairman was Albert Thomas, and he collected evidence world-wide, about working conditions. He wrote a code of good practice, which included:


See diagram above. Special departments dealt with specific world problems.


The first Secretary General was Sir. Eric Drummond, and he led the League’s administration department (Civil Service). He was in charge of:


Some nations joined the League late, e.g. Germany in 1926, USSR in 1934. 18 nations left the League, e.g. Germany in 1933 because other nations would not disarm to her level, Japan in 1933 after invading Manchuria, Italy in 1937 after invading Abyssinia, USSR in 1939 dismissed after the Nazi-Soviet Pact.


League of Nations at Work (1920-1939)

1. Its success in achieving its second aim

(To improve living conditions for men and women world-wide)

  1. The ILO was so successful that the USA joined it. In 1945 it transferred to the UNO.
  2. The Health Commission stopped disease epidemics (e.g. measles)
  3. The Leprosy Commission helped eliminate leprosy.
  4. The Transit and Communication Commission standardised passports and visas, and radio codes were also made common. (Mayday was internationalised.)
  5. The Mandates Commission, under Lord Lugard, helped colonies to reach independence.
  6. Doctor Nansen helped resettle homeless and stateless people from the Refugee Commission.

2. League’s failure in its first aim

(To keep peace)

a. The powers improved international relations in the 1920s, rather than the League

(see notes on interwar diplomacy)

b. The League did settle a few minor disputes in the 1920s

However, in the Corfu incident (1923) it had to refer the problem to the powers to solve.

i. Finland against Sweden (1920-21)

Finland and Sweden were in dispute over the Aaland Islands in the Baltic Sea. The League settled in favour of Finland.

ii. Germany against Poland (1921-22)

Germany and Poland disputed control of Upper Silesia. The League settled in favour of Poland: an unpopular decision (with the German speaking people of Upper Silesia, who said, quite rightly, that they had been denied NSD.)

iii. Italy against Greece (1923)

Italy held Greece responsible for the death of some Italian Officers on the frontier of Albania and Greece. Greece refused to compensate Italy for the loss, and so Italy bombarded the Greek island of Corfu. The League was approached about the conflict and referred the dispute to a Congress of Ambassadors who persuaded Greece to make a financial settlement, after which Italy evacuated Corfu (NB. The powers were keeping peace, again.)

c. The League Failed to bring about Multilateral Disarmament

  1. 1923 – The Draft Treaty of Mutual Assistance
  2. 1924 – The Geneva Protocol.

    Both of these asked for a level of disarmament, but were rejected.

  3. 1923-4 – Geneva Disarmament Talks (including USA and USSR)

    This failed because France still felt insecure, and would not disarm. In October 1933 Hitler withdrew from the talks stating that if other powers did not reduce the level of their arms to Germany’s level, he would rearm Germany to their level.

  4. NOTE: The only successful step towards disarmament took place at Washington (1921-2, Naval Sizes in Pacific.) This was hosted by the USA, not the League of Nations.

d. The League failed to control major crises in the 1930s

The Manchurian Crisis (see map 1)

18th September 1931, Japanese troops invaded Manchuria and attacked the industrial city of Mukden. Chiang Kai Shek (Chinese nationalist Leader) appealed to the League and to the USA for help. America protested and the League made a ‘Moral sanction’ and sent a Commission to Manchuria led by Lytton whose report condemned Japanese aggression. Unperturbed Japan renamed Manchuria, ‘Manchukuo’ in March 1932, and continued to occupy it. In 1933 Japan left the League of Nations. The big powers were more concerned with domestic issues (National interests came before the League’s affairs). Japanese aggression was not halted, the League’s ‘collective action’ had amounted to nothing.

NB. Only Germany and Italy recognised Japan’s control in ‘Manchukuo’.

The Abyssinian Crisis 1935-6 (see map 2)

This involved the aggression of Italy, led by Mussolini, in Abyssinia (now Ethiopia). Mussolini wanted to create a Fascist Roman Empire and saw the Horn of Africa as an ideal area for expansion. Italy already controlled Libya, Eritrea and Italian Somaliland so Abyssinia would help link its possessions. Italy had unsuccessfully tried to conquer the area in 1896. In October 1935 Mussolini was successful against the meagre troops of Emperor Haile-Salassie. Abyssinia appealed to the League and within two weeks Mussolini’s actions were condemned and economic sanctions were imposed. These sanctions were not very good because Italy still managed to obtain steel, copper and oil. The League did ban arms sales to Italy, but made Abyssinia weak by not letting it have any arms either! Mussolini did not take the League’s sanctions seriously and he threatened war if his oil supplies were stopped. Anthony Eden of Britain argued in favour of an oil embargo but the issue was complicated by secret diplomacy.

Hoare-Laval Pact (December 1935)

Samuel Hoare (GB) and Laval (France) made an agreement that if Mussolini stopped fighting, he could have most of Abyssinia. The world press published the pact, Hoare resigned and the agreement failed. Meanwhile Mussolini conquered Abyssinia entering Addis Ababa in May 1936 and Haile-Salassie fled.

Mussolini had said ‘If the League had extended economic sanctions of oil I would have had to withdraw from Abyssinia in a week".

The League had bungled its negotiations and had, once again failed miserably to maintain peace.

NOTE: The Abyssinian affair destroyed the ‘Stresa Front’. Britain and France had been meeting with Mussolini at Stresa in an attempt to unite against Hitler’s Germany. The actions of Hoare and Laval caused Italy to side with Germany henceforward.

The League of Nations failed because it was weak from the start

Ideal League League in Practice was Weak
1. All nations should be members. Not all nations were members (e.g. USA)
2. All nations should be equal partners in the League. Not equal partners because major powers made decisions in the Council.
3. The League should be able to make decisions quickly and easily. League structure was weak, unanimity caused delays.
4. National interests should be second to the league’s interests. Nations were more interested in their OWN affairs, especially after 1929 with the economic crisis.
5. Members should obey the League’s sanctions:
  1. The Moral Sanction
  2. The Economic Sanction
  3. The Military Sanction
  1. It was ignored (e.g. Japan in Manchuria – 1931)
  2. Offenders could trade with none League members (e.g. Abyssinia Crisis – 1935/6)
  3. It was silly to use violence to stop violence
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