The mutual defense treaty the Ottoman Empire made with Germany, saw the Ottoman Empire joined the Central Powers during World War I, and hence getting the Ottoman Empire embroiled in a conflict with Great Britain and France.
In 1915, the Hussein-McMahon Correspondence formed an agreement between United Kingdom and Arab leaders who declared that the Arabs would revolt in alliance with the United Kingdom, and in return the UK will recognize the Arab independence and grant sovereignty to Arab lands under Ottoman control.

The Hussein-McMahon Correspondence, is a protracted exchange of letters (July 14, 1915 to January 30, 1916) during World War I, between the Sharif of Mecca, Husayn bin Ali, and Sir Henry McMahon, British High Commissioner in Egypt, concerning the future political status of the lands under the Ottoman Empire,
Apparently, the Arab side was already looking toward a large revolt against the Ottoman Empire and the British encouraged the Arabs to revolt and thus hamper the Ottoman Empire, which had become a German ally in the War after November 1914.
Both the Jewish and the Arab population in Palestine at that time also chose to support the alignment of the United Kingdom, France, and Russia during World War I hoping Palestine will be released from the control of the Ottoman Empire.
However, the Balfour Declaration in 1917 proposed to “favour the establishment in Palestine of a national home for the Jewish people, but that nothing should be done to prejudice the civil and religious rights of the existing non-Jewish communities in Palestine.”

In 1917, the British succeeded in defeating the Ottoman Turkish forces and occupied the Palestine region. The land remained under British military administration for the remainder of the war.
Later, in 1917 Sykes–Picot Agreement between France and UK was exposed where the two countries were actually planning to split and occupy parts of the promised Arab country.
On January 3, 1919, future president of the World Zionist Organization Chaim Weizmann and the future King Faisal I of Iraq signed the Faisal-Weizmann Agreement for cooperation in the Middle East in which Faisal conditionally accepted the Balfour Declaration based on the fulfillment of British wartime promises of development of a Jewish homeland in Palestine.
Faisal’s agreement with Weizmann led the Palestinian Arab population to reject the Syrian-Arab-Nationalist movement led by Faisal (in which many previously placed their hopes) and instead to agitate for Palestine to become a separate state with an Arab majority.
In May 1939 the British government released a new policy paper which sought to implement a one-state solution in Palestine, significantly reduced the number of Jewish immigrants allowed to enter Palestine by establishing a quota for Jewish immigration which was set by the British government in the short-term and which would be set by the Arab leadership in the long-term.The quota also placed restrictions on the rights of Jews to buy land from Arabs, in an attempt to limit the socio-political damage.
These restrictions remained until the end of the mandate period, a period which occurred in parallel with World War II and the Holocaust, during which many Jewish refugees tried to escape from Europe.
As a result, during the 1930s and 1940s the leadership of the Yishuv arranged a couple of illegal immigration waves of Jews to the British Mandate of Palestine, which caused even more tensions in the region.

During the 1936–1939 Arab revolt in Palestine ties were made between the Arab leadership in Palestine and the Nazi movement in Germany.
These connections led to cooperation between the Palestinian national movement and the Axis powers later on during World War II.
In May 1941 Amin al-Husayni issued a fatwa for a holy war against Britain. In 1941 during a meeting with Adolf Hitler, Amin al-Husayni asked Germany to oppose, as part of the Arab struggle for independence, the establishment of a Jewish national home in Palestine.
He received a promise from Hitler that Germany would eliminate the existing Jewish foundations in Palestine after the Germans had gained victory in the war.
During the war Amin al-Husayni joined the Nazis, serving with the Waffen SS in Bosnia and Yugoslavia. In addition, during the war a joint Palestinian-Nazi military operation was held in the region of Palestine.
These factors caused deterioration in the relations between the Palestinian leadership and the British, which turned to collaborate with the Yeshuv during the period known as the 200 days of dread.
The newly formed United Nations subsequently recommended that Mandatory Palestine be split into three parts—a Jewish State with a majority Jewish population, an Arab State with a majority Arab population, and an International Zone comprising Jerusalem and the surrounding area where the Jewish and Arab populations would be roughly equal.
Resolution 181 decided the size of land allotted to each party.
The Jewish State was supposed to be roughly 5,700 square miles (15,000 km2) in size and was supposed to contain a sizable Arab minority population.
The Arab state was supposed to comprise roughly 4,300 square miles (11,000 km2) and would contain a tiny Jewish population. Neither state would be contiguous.
Jerusalem and Bethlehem were to be put under the control of the United Nations.
Neither side was satisfied with the Partition Plan.
The Jews disliked losing Jerusalem—which had a majority Jewish population at that time—and worried about the tenability of an uncontiguous state.
However, most of the Jews in Palestine accepted the plan, and the Jewish Agency (the de facto government of the Yishuv) campaigned fervently for its approval.
The more extreme Jewish groups, such as the Irgun, rejected the plan.
The Arab leadership argued that it violated the rights of the majority of the people in Palestine, which at the time was 67% non-Jewish (1,237,000) and 33% Jewish (608,000).
Arab leaders also argued a large number of Arabs would be trapped in the Jewish State. Every major Arab leader objected in principle to the right of the Jews to an independent state in Palestine, reflecting the policies of the Arab League.
The UN General Assembly voted on the Partition Plan on November 29, 1947. 33 states voted in favor of the Plan, while 13 countries opposed it. 10 countries abstained from the vote.
In favour: 33
Australia, Belgium, Bolivia, Brazil, Byelorussian S.S.R., Canada, Costa Rica, Czechoslovakia, Denmark, Dominican Republic, Ecuador, France, Guatemala, Haiti, Iceland, Liberia, Luxemburg, Netherlands, New Zealand, Nicaragua, Norway, Panama, Paraguay, Peru, Philippines, Poland, Sweden, Ukrainian S.S.R., Union of South Africa, U.S.A., U.S.S.R., Uruguay, Venezuela.
Against: 13
Afghanistan, Cuba, Egypt, Greece, India, Iran, Iraq, Lebanon, Pakistan, Saudi Arabia, Syria, Turkey, Yemen.
Abstained: 10
Argentina, Chile, China, Colombia, El Salvador, Ethiopia, Honduras, Mexico, United Kingdom, Yugoslavia.
The Yishuv accepted the plan, but the Arabs in Palestine and the surrounding Arab states rejected the plan.
The Arab countries (all of which had opposed the plan) proposed to query the International Court of Justice on the competence of the General Assembly to partition a country against the wishes of the majority of its inhabitants, but were again defeated.
The division was to take effect on the date of British withdrawal from the territory on May 15, 1948.

On March 10, 1948, the Jewish defense force Haganah issued “Plan D (“Dalet”) claiming it was a vision for defending the newly emerging state of Israel. Palestinians saw it differently: as a set of concrete steps by Zionists to subject Palestine to an ethnic cleansing of Arabs.
On April 9, 1948, the Irgun, one of whose commanders is Menachem Begin, and the Stern Gang, commanded by Yitzak Shamir, stormed the Arab village of Deir Yasin. Two hundred and fifty people, over one hundred of whom were women and children, were massacred. The event struck terror among the Arabs, causing 300,000 Arabs fled Palestine.
On May 14, 1948, one day before the British Mandate expired, and before the bulk of the remaining British troops departed from Palestine, the first Prime Minister of Israel, David Ben-Gurion, self-declared the formation of the state of Israel on Palestine land, though without specifying borders.
The next day, the Arab League reiterated officially their opposition to the “two-state solution” in a letter to the UN. Whilst on 15–16 May, the four armies of Jordan, Syria, Egypt and Iraq invaded the newly self-declared state followed not long after by units from Lebanon.
Prior to and during this conflict, a large exodus of 713,000 Palestinian Arabs fled their original lands to become Palestinian refugees, in part, due to an alleged promise from Arab leaders that they would be able to return when the war had been won. Whilst Arab commanders ordered villagers to evacuate for military purposes in isolated areas, there is no evidence that the Arab leadership made a blanket call for evacuation and in fact most urged Palestinians to stay in their homes.
Nevertheless, assaults by the Haganah on major Arab population centers like Jaffa and Haifa as well as expulsions carried out by groups like the Irgun and Lehi such as at Deir Yassin and Lydda that are now the present-day Israel led to the exodus of large portions of the Arab masses out of Palestine.
Factors such as the earlier flight by the Palestinian elite and the psychological effects of Jewish atrocities (stories which both sides propagated) also played important roles in the Palestinian flight.
The war resulted in an Israeli victory, with Israel annexing territory beyond the partition borders for a proposed Jewish state and into the borders for a proposed Palestinian Arab state.
The remaining territories, the Gaza Strip and the West Bank, were occupied by Egypt and Transjordan, respectively.
Jordan also annexed East Jerusalem while Israel administered West Jerusalem. In 1950, The West Bank was unilaterally incorporated into Jordan.
The War came to an end with Jordan, Syria, Lebanon, and Egypt signed the 1949 Armistice Agreements with Israel.
Over 700,000 Jews emigrated to Israel between 1948 and 1952, with approximately 285,000 of them from Arab countries. By the late 1960s, more than 850,000 Jews had left their birthplaces and their homes in some 10 Arab countries that these immigrant Jews and their descendants represent 41% of the total population of Israel today.
Then again the defeat of the Arab countries in the Six-Day War with Israel in 1967 prompted fractured Palestinian political and militant groups to give up any remaining hope they had placed in pan-Arabism.
Palestine, unlike Israel, had not exercised its rights to self-declare formation of the state of Palestine to become a sovereign state by the date of British withdrawal from the territory on May 15, 1948, pursuant to UN General Assembly Resolution 181 on Partition Plan 1947, to co-exist with the state of Israel on Palestine soil.
This gave the Israelis subsequent support for their argument that they did not occupy sovereign territories of Palestine for the sovereign state of Palestine has not existed. And therefore did not break the Fourth Accord of the Geneva Conventions and international law.
Now Palestinian Arabs are prevented from going back to that 1947 UN Partition Plan resolution to unilaterally declare the establishment of the separate Arab state of Palestine and apply for full UN membership, exactly the step Israel took 64 years ago in 1948 upon British colonial leaving the Palestine’s soil.
UN now insists that the 1949 Armistice (Green Line) territories comprising Gaza Strip, West Bank and East Jerusalem are presently not under Arab Palestine’s but Jewish Israel’s control, to satisfy basic requirements for unilateral declaration of an independent Arab state of Palestine on those territories.
Jordan annexed West Bank and East Jerusalem and Egypt annexed Gaza Strip after Arab-Israeli war of 1948 and both held them for 19 years until 1967 before re-captured by Israeli who initiated a surprised attack that saw Israel annexed Sinai Peninsula from Egypt and Golan Height from Syria as well.
Indeed that 19-year period between 1948 and 1967 had provided ample opportunity for both Egypt to release Gaza strip, while Jordan released West Bank and East Jerusalem, to be under Arab Palestine’s absolute control to enable Arab Palestinian declare undisputed formation of independent state of Arab Palestine as early as 1948. But it never happened.
While Egypt had since signed Israel-Egypt Peace Treaty in 1979 for the return of Sinai Peninsula and for Egypt to recognize and having full diplomatic relations with Israel, which was followed by Jordan who signed Israel-Jordan Treaty of Peace in 1994 to accord full recognition of Israel and engaging on full diplomatic relations with Israel.
Meanwhile, acceptance of Arab Palestine’s full state membership in UNESCO on October 31, 2011 was met with this Israeli’s cynical remark: “We regret that the organization of science has opted to adopt a resolution which is a resolution of science fiction,” said Nimrod Barkan, Israel’s ambassador to UNESCO, who called the move a tragedy for the agency. “There is no Palestinian state and therefore one should not have been admitted today.”
If Arab Palestine is prevented from unilateral declaration for establishment a new and separate sovereign state of Palestine on Palestine’s soil for having no control over Gaza Strip and West Bank now annexed to Israel. And that Arab Palestine will not be recognized a sovereign state to be accepted as full member of UN to force the Zionist regime of Israel to withdraw from the occupied sovereign territories of Arab Palestine, the right Arab Palestine had been accorded by the world’s body itself under resolution 181 partition plan of 1947 in the first place, then what UN expects Arab Palestinians to do?
God helps them..