The Balfour Declaration began as British policy in a letter dated 2 November 1917. Its international legal significance changed when the League of Nations approved the Mandate for Palestine on 24 July 1922; the Mandate came into force on 29 September 1923. The preamble says the Mandatory power would put the declaration into effect and recognizes the Jewish people’s historical connection with Palestine. These steps gave Britain defined international responsibilities, not immediate sovereignty to a state.
What the Mandate required Britain to do
Article 2 made Britain responsible for placing the country under political, administrative, and economic conditions that would secure the Jewish national home, develop self-governing institutions, and safeguard the civil and religious rights of all inhabitants, irrespective of race or religion. Article 4 recognized a Jewish agency as a public body to advise and cooperate with the administration; Article 6 addressed immigration and close Jewish habitation on the land. The League’s Mandate text sets out these provisions directly.
In 1922, the League approved application of Article 25 to Transjordan, excluding it from provisions concerning the Jewish national home. That was a measure within the Mandate framework, not a retroactive revision of the 1917 letter. The exact instruments and dates matter: Balfour was a British declaration; the Mandate was an international instrument assigning Britain administrative powers and obligations.
What the instruments did not decide
Neither text declared a Jewish state or set a final sovereignty arrangement. The Mandate’s language about “reconstituting” the national home recognizes historical connection; it does not itself state that ancient sovereignty was legally restored. Article 80 of the 1945 UN Charter refers to rights of states and peoples and terms of existing international instruments in the context of the UN trusteeship system. Its application to specific Mandate claims is disputed, so it cannot be presented as an uncontested, blanket guarantee of sovereignty.
The accurate conclusion is narrower and substantial: the League embedded support for the Jewish national home in Britain’s mandate responsibilities, alongside other stated obligations. See the original declaration and the wartime documents that preceded it.