From a 1980 Yale Journal of International Law article:
"Palestinian Self-Determination": Possible Futures for the Unallocated Territories of the Palestine Mandate
by Eugene V. Rostow
There is no foundation in international law for the idea of a second Arab Palestinian state in the West Bank and the Gaza Strip. And it would be political and military folly for the West to force Israel to acquiesce in such a scheme. Establishing a new Arab state there would injure Western interests, and advance those of the Soviet Union, by strengthening the Soviet position in the region, and by increasing Arab dependence on Soviet protection. It would weaken Israel, which, since the fall of Iran, is the most important Western ally in the area.
Above all, such a policy would abandon the moral and political obligations towards Israel which the victorious Allies assumed in 1919, and reiterated through the United Nations Charter in 1945. Israel's legitimacy as a state rests on much more than the usual criteria of international law--de facto statehood; membership in the United Nations; recognition; the success of its armed forces; the weight of history; and so on. In 1922, the organized international community of the day, the League of Nations, with the special concurrence of the United States, which was not a member, established the Palestine Mandate. Through that Mandate, it invited Jews to come to live in Palestine as their national home, In reliance on that promise, the Jewish community in Palestine developed, and, with the approval of the Security Council and the General Assembly of the United Nations (the successor to the League), became the state of Israel. The solemn obligations of the international community to Israel implicit in these events survive not only as a special moral and historic element in Israel's status within the family of nations, but as a trust still applicable, with other norms and interests, to the task of fashioning a just and durable future for the West Bank and the Gaza Strip.
For the West to betray those commitments would be to take another long step towards dissolving the world community organized as the United Nations into a condition of universal war.