"Neither customary international law nor the United Nations Charter acknowledges that every group of people [Palestinian Arabs included] claiming to be a nation has the right to a state of its own." 
The Mandate for Palestine, a legally binding document under international law, clearly differentiates between political rights referring to Jewish self-determination as an emerging polity and civil and religious rights, referring to guarantees of equal personal freedoms to non-Jewish residents as individuals and within select communities. Not once are Arabs as a people mentioned in the Mandate for Palestine. At no point in the entire document is there any granting of political rights to non-Jewish entities (i.e., Arabs). Article 2 of the Mandate for Palestine explicitly states that the Mandatory should:
Be responsible for placing the country under such political, administrative and economic conditions as will secure the establishment of the Jewish national home, as laid down in the preamble, and the development of self-governing institutions, and also for safeguarding the civil and religious rights of all the inhabitants of Palestine, irrespective of race and religion.
Political rights to self-determination as a polity for Arabs were guaranteed by the League of Nations in four other mandates in Lebanon and Syria [The French Mandate], Iraq and later Trans-Jordan [The British Mandate]. Political rights in Palestine were granted to Jews only.
International law expert Professor Eugene V. Rostow, examining the claim for Arab Palestinian self-determination on the basis of law, concluded:
The mandate implicitly denies Arab claims to national political rights in the area in favor of the Jews; the mandated territory was in effect reserved to the Jewish people for their self-determination and political development, in acknowledgment of the historic connection of the Jewish people to the land. Lord Curzon, who was then the British Foreign Minister, made this reading of the mandate explicit. There remains simply the theory that the Arab inhabitants of the West Bank and the Gaza Strip have an inherent natural law claim to the area.
 See Eugene V. Rostow, The Future of Palestine, Institute for National Strategic Studies, November 1993. Professor Rostow was Sterling Professor of Law and Public Affairs Emeritus at Yale University and served as the Dean of Yale Law School (1955-66); Distinguished Research Professor of Law and Diplomacy, National Defense University; Adjunct Fellow, American Enterprise Institute. In 1967, as U.S. Under-Secretary of State for Political Affairs, he became a key draftee of UN Resolution 242. See also his article: Are Israels Settlements Legal? The New Republic, October 21, 1991.