Bolded part above, the British plan was for so many a year to go, not come in like locusts. Also they disregarded the lines. They went with intent to take over all of Palestine.
Yep, the Brits were losing in WW I, they were ready to sign an agreement with Germany, but then Zionists came to the Brits and proposed a deal:
You invade the Palestine and give it to us, and we promise you that USA will get involved in WW I.
After that all American papers, who only a month ago supported Germany in her war effort against Russia started the modernization of Germany, and USA eventually got involved in WW I.
If there was no Zionist, there would be no Balfour Declaration, no Bolshevik Revolution in Russia, no dismemberment of Germany after WW I, and therefore no WW II, no Nakba... and no Israel.
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.
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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.
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The Balfour Declaration radically changed the status of the Zionist movement. It promised support from a major world power and gave the Zionists international recognition.
Zionism was transformed by the British pledge from a quixotic dream into a legitimate and achievable undertaking.
Palestine During World War I Jewish Virtual Library
Strange then how the Bolshevik's were a force before WW1, and looked to rule Russia