The last of Woodrow Wilson's Fourteen Points spoke of a general association of nations, which would guarantee the independence and integrity of all members against aggression - a system of 'collective security' to be backed by compulsory arbitration and enforcement.
British ambitions were more modest - the Phillimore Commission of January and March 1918 recommended that before going to war nations should submit disputes for arbitration by a council of members. Economic or military sanction would be enforced against those that broke the rules.
The League of Nations was a compromise between the two. It consisted of a Council made up of the Great Powers as permanent members, and six temporary members making up the General Assembly. Countries that defied the League would face the military and economic power of the collective membership. A unanimity clause was part of the League's covenant - recommendations had to be unanimous to come into effect. Article 15, on the peaceful settlement of disputes, was the exception. It specified that in a dispute, parties would not vote on Council or Assembly recommendations. The League was founded in 1919, and in January 1920 the first Council meeting took place in Geneva.
The potential effectiveness of the League was undermined when, after the Senate failed to ratify the Versailles Peace Treaty with Germany in March 1920, the US withdrew. The US further undermined the League's credibility by working outside its framework and brokering the Washington Conference of 1921 and 1922 concerning naval disarmament of the Great Powers relations in the Far East. Although Germany joined the Council as a permanent member in 1926, and the USSR in 1934, the League centred on Western Europe.
During the 1920s the League had some successes in collective security. During 1925 skirmishes on the Greek/Bulgarian border were followed by a Greek invasion. Bulgaria appealed to the League, which called for an immediate end to hostilities, refusing to negotiate on behalf of Bulgaria until all troops had been withdrawn. The League threatened Greece with sanctions under Article 16 of the covenant and Greece agreed to withdraw and pay an indemnity. In this dispute, however, the Council members were in agreement and had no national interest.
Britain also took a dispute between the Persian government and the Anglo-Persian Oil Company to the League, which was successful in mediating for concessions.