Juan Cole in TruthDig:
The map is useful and accurate. It begins by showing the British Mandate of Palestine as of the mid-1920s. The British conquered the Ottoman districts that came to be the Mandate during World War I (the Ottoman sultan threw in with Austria and Germany against Britain, France and Russia, mainly out of fear of Russia).
But because of the rise of the League of Nations and the influence of President Woodrow Wilson’s ideas about self-determination, Britain and France could not decently simply make their new, previously Ottoman territories into mere colonies. The League of Nations awarded them “Mandates.” Britain got Palestine, France got Syria (which it made into Syria and Lebanon), Britain got Iraq.
The League of Nations Covenant spelled out what a Class A Mandate (i.e. territory that had been Ottoman) was:
“Article 22. Certain communities formerly belonging to the Turkish Empire have reached a stage of development where their existence as independent nations can be provisionally recognised subject to the rendering of administrative advice and assistance by a Mandatory [i.e., a Western power] until such time as they are able to stand alone. The wishes of these communities must be a principal consideration in the selection of the Mandatory.”
That is, the purpose of the later British Mandate of Palestine, of the French Mandate of Syria, of the British Mandate of Iraq, was to ‘render administrative advice and assistance” to these peoples in preparation for their becoming independent states, an achievement that they were recognized as not far from attaining. The Covenant was written before the actual Mandates were established, but Palestine was a Class A Mandate and so the language of the Covenant was applicable to it. The territory that formed the British Mandate of Iraq was the same territory that became independent Iraq, and the same could have been expected of the British Mandate of Palestine. (Even class B Mandates like Togo have become nation-states, but the poor Palestinians are just stateless prisoners in colonial cantons).
More here.