Anglo-American relations throughout the Second World War and the years that followed, were at times coloured by the history of Zionism. This was the result of transfer of the Zionists' main effort from London to Washington in the hope of capitalizing on, and increasing, Zionist pressure there. The Zionists, faced with abandonment of British support for their aspirations in Palestine, due to strategic considerations, hoped that American intervention in British Palestine policy might cause Britain to resume that support. But no serious American attempt was made to prevent the introduction, in May 1939, of the British anti-Zionist White Paper policy. This lack of American pressure continued throughout the war. But as soon as the war ended, active American intervention began. The result, according to the evidence of the British Foreign Minister of the time (Bevin), was Britain's decision to abandon Palestine. This thesis endeavours to show the course of these Anglo-American relations, and to describe the development of the forces that prompted and perpetuated this American intervention. The thesis shows how in a first phase, which lasted until the beginning of 1943, the Government of the United States was reluctant to intervene for virtually the same reasons as governed the change in British policy that dates from 1938, when in face of the Axis threat they abandoned their attempt to impose the partition of Palestine and sought to maintain relations with the Arabs that would be good enough to suit their strategic ends. Consequently, throughout the war, world Jewry was faced with a grim combination of Nazi persecution of the Jews in Europe--later to become their total extermination --and the closing of the asylum of Palestine by the British. This combination had two main effects on the Jews: in America it enhanced the recruitment of the majority of Jews to the ranks of the Zionist movement, while in Palestine it reinforced Jewish determination to fight the White Paper, even by resort to violence. The common characteristic of both developments was the increase in Zionist impatience and Zionist militancy. In the course of that development, American Zionists, inspired by visitors from London and Palestine, pursued a dream that realists considered impossible of fulfilment. Before anyone in America knew the full dimensions of the holocaust and before victory in the war seemed in any way assured, the American Zionists illustrated their belief that "the hour of redemption would soon strike," and produced the "Biltmore" programme. These American Zionists believed that a Jewish State in the whole of Palestine, should be given to them "by the world", at the end of the war, and that this was going to be the true outcome of Jewish suffering. In the second phase, which ran between the beginning of 1943 and the end of the war, their Messianic dream gradually turned into a political programme. 1943 was the year in which the German threat to the Middle East came to an end. As the Allies' victory loomed in sight, not only the Zionists, but both the British and the United States began to consider the future of Palestine. The British Cabinet, largely under the influence of Churchill, saw the final phase of the war as providing it a better chance to tackle the problem than the post-war era was likely to be. Before long, it reached the conclusion that the White Paper must be replaced by a partition and accordingly drew up concrete plans. Significantly, however, the Cabinet decided to make its stand secret, until implementation of its plan was possible. It decided to exclude even the United States from knowledge of it. In consequence, an asymmetric relation developed between the two powers in which the British were told of American schemes and proposals for Palestine (most of which were merely random improvisations) but did not tell the Americans their own. The relationship amounted to a dialogue of the deaf. When, for reasons that this thesis will explain, the chance to implement partition was missed, Britain appeared to the Americans, as well as to the rest of the world, as doggedly adhering to the White Paper policy. This impression both increased Zionist beligerency, helping to make the post-war British position in Palestine impossible, and hardened the attitude of President Truman, causing him to start intervening. After 1943, two conflicting tendencies developed simultaneously in America, both affecting Middle Eastern policy. On the one hand, a scare about oil shortage and about other American interests in the Middle East, awakened an American wish to win Arab goodwill. On the other hand, mounting Zionist and (through Zionist effort) American public pressure on the Administration, brought about growing support for Zionist aspirations, particularly in Congress. This coincidence of pressures became a source of profound embarrassment to United States foreign policy makers. Since the British were at the same time disturbed by the prospects of growing difficulties in Palestine, springing from growing Jewish militancy, the one sense in which the two governments co-operated during the war in regard to Palestine was in an attempt to damp down Zionist agitation. This attempt gave birth to plans for a joint statement, condemning this agitation as impeding the Allied war effort; but the Zionists and their supporters managed to defeat this move. The result of the inner embarrassment caused to Americans was an ambiguous policy, according to which soothing statements were simultaneously made both to Jews and to Arabs only the former received these reassurances publicly; the latter learned of them in secret. This "two-way-talk" policy reached its peak towards the end of the war. Before Roosevelt's death, in April 1945, he had reached the conclusion that a Zionist solution in Palestine was impossible to implement and to maintain without resort to force. This conclusion led him to abandon his earlier support for it and to seek solutions of a different character. He, however, did not have the time or the readiness to develop his ideas much further. In his last year in office, Roosevelt struggled to stem the mounting Zionist pressure on his administration. After his failure to issue the Anglo-American statement, he scored a temporary success by managing to shelve pro-Zionist resolutions in Congress. But he was ail-but completely disarmed during the 1944 election campaign. This campaign was marked by a flood of pro-Zionist utterances, made by both political parties and their candidates for the Presidency, as a result of skilful Zionist tactics; in this election campaign, as they were again to do in the future, the Zionists instead of adhering to one Party, as they had done in the past, put their vote up to auction. Nevertheless, politically, the American Zionists achieved very little during the war. Their only impressive success was the mass recruitment of Jewry itself. All their other seeming achievements, in the form of platforms and statements and promises, seemed, when the war ended, to have vanished into thin air. But the same happened to all the plans and schemes proposed during the war by Britain and the United States. Palestine was not discussed at Yalta and formed no part of mutual post-war arrangements. The secret partition plan of the British Cabinet lay in ruins and all the other alternatives looked just as unpalatable. What remained intact was the White Paper. In the third phase, which ran from the end of the war until early 1947, American intervention began and developed. But it did not take the form for which the American Zionists had hoped; nor did it in the end bring about the results they desired.