The declaration was opposed by Arab public opinion but after the war it was endorsed by the victorious allies and it became official British policy. It was supported by the Americans but they had some reservations. Many in the British government believed that the Balfour Declaration was a mistake and that it would only lead to instability and conflict and that it had no basis in international law and
believed that they had betrayed their Arab allies who had participated in the Great Arab Revolt (1916-1918). However, the Balfour Declaration remained, and it was official British policy until the start of WWII. This was despite increasingly violent Arab opposition. The Balfour Declaration and the failure of the western powers to grant a Pan-Arab state led to a great deal of resentment in the Middle East. The British not only had failed to help the Arabs to found a state but had effectively colonized them and had even given traditionally Muslim territory to non-Muslims. What particularly angered the Arabs was that Jerusalem one of the holiest sites in Islam could be lost to Jews. This led to a deep suspicion of Britain and the west in general, in the Arab World. During WWI the Arabs had seen the British as liberators who would help to modernize their society and free them from Ottoman oppression. The Balfour Declaration was to shatter this view and led to a great deal of bitterness. The Muslim world in particular came to believe that it could not trust the British and the west. The anti-western sentiments that were provoked by the Balfour Declaration remain to this day. The Declaration of 1917 poisoned the relationship between the Arab World and the West. It persuaded many that the western powers would always favor the Jews at the expense of the Muslims in the Middle East.
[[File: Hachshara.jpg|200px|thumb|left|Jewish settlers in Palestine in the 1920s]]
==Balfour Declaration and the state of Israel==
Zionists during the Ottoman period had begun to emigrate to Palestine, in what is known as the Aliyah or the return. In general, the Jewish emigrants had co-existed with their neighbors. The two communities tended to live separate existences with little interactions between them and even less understanding. This changed with the defeat of the Ottoman Empire in 1918<ref> Ben-Ami, Shlomo. Scars of War, Wounds of Peace: The Israeli-Arab Tragedy Weidenfeld & Nicolson, 2005), p 201</ref>. The British under the mandate from the League of Nations established the political entity of Palestine that corresponds to the modern state of Israel. This aroused Arab fears. The British established a political and bureaucratic system in the region and it became part of their Empire. In general, the British officials were sympathetic to the Jews and were biased in their favor. The Balfour Declaration meant that the British administration in Palestine had to support the Jewish community and any Jewish emigrants who wanted to settle in the area. Because of the Balfour Declaration, any Jew who wished could come from any area of the globe and settle in Palestine. As a result, many Muslim areas such as Haifa came to have a predominantly Jewish population <ref> Goren, Tamir (2004). The Judaization of Haifa at the Time of the Arab Revolt. Middle Eastern Studies, Volume 40, Issue 4 July, pp. 135–152 </ref>. The British made several concessions to the Jews. Hebrew was accorded equal status with Arabic in the government. The British government tended to employ more Jews than Muslims. The Balfour Declaration encouraged many Jews to settle in Palestine as they believed that the declaration of a Jewish state was imminent. Many Jews fleeing the Russian Civil War settled in Palestine<ref>Ben-Ami, p. 213</ref>. These joined the existing Jewish community and together established settlements, farms, and Kibbutz, these are communal farms. Soon there was a thriving Jewish community and by 1939 the Jews were one-third of the population of the region. The numbers of Jews though small grew rapidly and the developed prosperous and resilient Jewish communities. These were very important in the foundation of the Jewish state. The settlers who came to Palestine, in the Aliyah formed the nucleus of modern Israel. If the Balfour Declaration had not encouraged and facilitated Jewish emigration, then there may not have been any state of Israel<ref>Gelvin, p.123</ref>.