What did the British promise to the Jews?
The British pledge that formally committed the British to the Zionist cause, was the Balfour Declaration of November 1917, an instrument created after the Husayn-McMahon Correspondence and the Sykes-Picot Agreement.
Before the emergence of David Lloyd George as prime minister and Arthur James Balfour as foreign secretary in December 1916, the Liberal Herbert Asquith government had viewed a Jewish entity in Palestine as detrimental to British strategic aims in the Middle East. Lloyd George and his Tory supporters, however, saw British control over Palestine as much more attractive than the proposed British-French condominium. Since the time of the Sykes-Picot Agreement, Palestine had taken on increased strategic importance because of its proximity to the Suez Canal, where the British garrison had increased to 300,000 men, and because of a planned British attack on Ottoman Syria originating from Egypt. Lloyd George was determined, as early as March 1917, that Palestine should become British and that he would rely on its conquest by British troops to obtain the abrogation of the Sykes-Picot Agreement.
In the new British strategic thinking, the Zionists appeared as a potential ally capable of safeguarding British imperial interests in the region. Furthermore, as British war prospects dimmed throughout 1917, the War Cabinet calculated that supporting a Jewish entity in Palestine would mobilize America's influential Jewish community to support United States intervention in the war and sway the large number of Jewish Bolsheviks who participated in the 1917 Bolshevik Revolution to keep Russia in the war. Fears were also voiced in the Foreign Office that if Britain did not come out in favor of a Jewish entity in Palestine the Germans would preempt them. Finally, both Lloyd George and Balfour were devout Christians who attached great religious significance to the proposed reinstatement of the Jews in their ancient homeland.
The negotiations for a Jewish entity were carried out by Chiam Weizmann, who greatly impressed Balfour and maintained important links with the British media. In support of the Zionist cause, his protracted and skillful negotiations with the Foreign Office were climaxed on November 2, 1917, by the letter from the foreign secretary to Lord Rothschild, which became known as the Balfour Declaration. This document declared the British government's "sympathy with Jewish Zionist aspirations," viewed with favor "the establishment in Palestine of a National Home for the Jewish People," and announced an intent to facilitate the achievement of this objective. The letter added the provision of "it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine or the rights and political status enjoyed by Jews in any other country."