In 1920, following WWI, the British obtained an official League of Nations mandate government over Palestine. During this time, with more money coming into the World Zionist Organization, the Zionist movement was able to buy up more and more land. This led to a significant increase in violence from Arab Palestinians in 1929, which alerted the British that the conflict that they'd enabled there between the Arab Palestinians and the Zionists was going to get ugly. The British started looking for ways to hand control (i.e. responsibility) over to someone else. They suggested various plans of partition – almost all of which were accepted by the Zionists and rejected by the Palestinian Arabs. The Zionists wanted whatever the British would give them. The Palestinian Arabs did not want anything less than a United Arab State in Palestine.

By the 1930s, Nazism had begun to spread throughout Europe. In Germany, Hitler was openly advocating Jewish expulsion. In Italy, Mussolini was following. And in response, Jewish immigration and land purchase in Palestine reached record levels. By the mid-1930s, Jews comprised nearly one-third of the total population in Palestine, though still owning only about 10% of the land. In reaction to these major demographic changes (and major economic changes – see following sections), the Palestinian Arabs attempted to take on the British mandate government in an economic protest in 1936, which turned violent. While British forces violently repressed this movement, the government did take notice. They issued the White Paper in 1939 that put severe restrictions on Jewish immigration and land purchase, and effectively negated the Balfour Agreement.

When Britain became totally absorbed in WWII, leaders in the Zionist movement initiated illegal immigration and settlement operations. The Zionist movement was simultaneously establishing state institutions in Palestine, supporting illegal immigration and land purchase, supporting the British in WWII, and planning their future attacks on the British mandate government, so that they could oust them after the war.

Jewish soldiers from Palestine who had enlisted to fight under the British brought their military training – and weaponry – back to the Haganah – the Jewish army in Palestine. In 1944, before WWII even ended, one of the Jewish underground militia groups started violent attacks on the British mandate government. As soon as the outcome of WWII looked certain, another Zionist militia group started attacking British government buildings, infrastructure, and bureaucrats. These groups were condemned by the mainstream Zionist movement until the end of the war, when the Haganah, with the backing of the Zionist leadership, joined in the now-organized guerilla warfare against the British mandate government.

In the meantime, Britain was experiencing an economic downturn, the US was experiencing the same downturn and they were demanding returns on the financial assistance they made to the British during the war. Due to the attacks on their infrastructure, Palestine had become an economic and political liability to the British, so they began to look for a way out.

A whole host of commissions and committees were set up by the British, the Americans, and the newly-formed United Nations to determine a solution for the conflict in Palestine. The Zionist movement knew they needed to sway public world opinion if they were going to win a Jewish state. They ensured that the tours the committee took to inform their decisions about the conflict, would begin not in Palestine, but in Europe, where delegates could meet Jews in displaced-persons camps and see the ravages of the Holocaust on the Jewish population. The Jewish survivors told committee members about their desire to settle in Palestine. "Most of the DPs [displaced persons] who did not initially wish to go to Palestine were persuaded quite easily that for the sake of the majority they should present a united Jewish front to the committee." When the committee traveled to Palestine, they were met with a grand reception by the Zionists, and effectively boycotted by the Arab Palestinians. Not surprisingly, the committee walked away almost totally on the side of the Zionists, citing the needs of European Jewry as one of their main concerns.

The first solution proposed a bi-national state under UN oversight – and was rejected by both the Zionists and Arab Palestinians. Various other plans also failed. Finally, thanks to an unlikely agreement between the United States and the Soviet Union, the UN passed the Partition Resolution in 1947, otherwise known as "Western civilization's gesture of repentance for the Holocaust."

The British pulled out, the Zionists took over nearly all of their bureaucratic institutions, and warfare began between Zionists and Palestinian Arabs. The Zionist military decimated Palestinian military forces and society, expelling over a million Palestinians into neighboring Arab countries. On May 14, 1948, they declared the establishment of a Jewish State: Israel. As promised, leaders of the surrounding Arab countries entered Israel, but even united, the Arab forces were outnumbered, out-resourced, and out-organized. The Zionist movement won the diplomatic battle and the military one – and their nationalist goals were realized.