"As I said earlier, violent conflicts on all sides had been going on since the 1920s, reached a peak during 1936-1939, and then resumed again in the immediate post-war period." - Steve

In stating the above you are partially correct.

The unprovoked attacks by Arabs on Jews in 1920 and again in 1921 combined with the manner in which those atrocities were dealt with by the British, did not inspire the Jewish community with any confidence as to the quality of protection they could expect under British administration. That having been said, it must also be clearly stated that there were no Jewish acts of reprisal to the Arab attacks.

The Jewish leadership created the Haganah to protect their farms and Kibbutzim. Had the Arabs not attacked, or had the British dealt with the cause of the trouble, the Haganah would never have existed.

In addition to guarding Jewish communities, the role of the Haganah was to warn the residents of and repel attacks by Palestinian Arabs. In the period between 1920–1929, the Haganah lacked a strong central authority or coordination. Haganah "units" were very localized and poorly armed: they consisted mainly of Jewish farmers who took turns guarding their farms or their kibbutzim.

Once again in 1929 there were further unprovoked attacks on Jews by Arabs. In terms of scale and seriousness these were much fiercer than the earlier attacks, and caused Haganah's role to changed dramatically. If possible British handling of these riots and their aftermath were even more inept than before and this convinced the Jewish community that the only people that they could rely on for their own defence was themselves. Again please note Steve that none of the Arab attacks of 1929 were responded to by way of reprisal by the Jewish community.

Haganah was expanded, it became a much larger organization encompassing nearly all the youth and adults in the Jewish settlements, as well as thousands of members from the cities. It also acquired foreign arms and began to develop workshops to create hand grenades and simple military equipment, transforming from an untrained militia to a capable underground army.

Within Haganah there was an official policy of havlagah (restraint) that Jewish political leaders imposed on their militia. Fighters had been instructed to only defend communities and not initiate counter attacks against Arab gangs or their communities. But in the aftermath of the 1929 attacks a splinter faction that believed in reprisal attacks came into being in 1931, the name of this organisation was Irgun. Irgun could have viewed as the direct counterpart to the al-Qassam, "Black Hand Group", an anti-zionist and anti-British militant organisation, organized and established in 1930 by Izz ad-Din al-Qassam. He recruited and arranged military training for peasants and by 1935 he had enlisted between 200 and 800 men. The cells were equipped with bombs and firearms, which they used to kill Jews in the area, as well as engaging in a campaign of vandalism of the Jewish-planted trees and British constructed rail-lines. It was the death of Izz ad-Din al-Qassam at the hands of the British that sparked off what became known as the Great Arab Revolt.

At the start of the Great Arab Revolt 1936 -1939, Haganah fielded 10,000 mobilized men along with 40,000 reservists. It participated actively to protect British interests and to quell Arab rebellion using the FOSH, and then HISH units. Although the British administration did not officially recognize the Haganah, the British security forces cooperated with it by forming the Jewish Settlement Police, Jewish Auxiliary Forces and Special Night Squads, which were trained and led by Colonel Orde Wingate, who later during World War II would go on to lead "Chindit 1" and "Chindit 2" operations behind Japanese lines in Burma.

During the first stage of the Revolt, Irgun and the Haganah generally maintained a policy of restraint. From April 1936 until October of that year, 80 Jews were killed, 369 were injured, 19 schools were attacked, nine orphanages and three old-age homes. 380 attacks on trains and buses were carried out, and approximately 4,000 acres of agricultural land were destroyed. These actions were carried out by armed Arab gangs who were joined by Syrian and Iraqi reinforcements.

There was a lull in activity while the Peel Commission investigated the unrest and the British Army began taking more stringent measures to curb the attacks.

All in all Irgun carried out 60 reprisal attacks ("eye-for-an-eye") during the Great Arab Revolt, resulting in the deaths of some 250 Arabs, the Arab attacks over the same period had killed 320 Jews.

During the Second World War, the Jews generally sided with the Allies, although a splinter group from Irgun, LEHI or Stern gang, commenced actions against the British from 1944. The Arabs generally remained neutral or sided with the Axis powers.

The Peel Commission realised that there would never be a single Palestinian State and that a two State solution must be sought. After the end of the Second World War the UN arrived at the same conclusion. The offer was made on 29th November 1947 and rejected by the Arabs who then attacked the Jews on the 30th.

Responsibility for the actual instigation of violence in Palestine from 1st March 1920 (Tel Hai) up to and including the presentation of the UN proposal for a two state solution on 29th November 1947, can be firmly laid at the door of the Palestinian Arabs, not once in that 27 year period was there any instance of civil unrest caused by a Jewish attack on anybody.

Had the Palestinian Arabs accepted what was offered on 29th November 1947 - which was as near as damn it what they are asking for now - then none of the rest of it would ever have happened.

As previously stated 60 years of bloodshed and grief, all for something that was on the table for them to accept in 1937 (Peel Commission) and again in 1947 (UN Partition Plan).