In the summer of 1946, Truman established a special cabinet committee into negotiations with a parallel British committee to discuss the future of Palestine. In May 1946, Truman announced his approval of a recommendation to admit 100,000 displaced persons into Palestine and in October publicly declared his support for the creation of a Jewish state. Throughout 1947, the UN Special Commission recommended the partition of Palestine into a Jewish and an Arab state. Soon, on November 29, 1947 the UN created Resolution 181 or Partition Resolution that divides Great Britain’s former Palestinian mandate into Jewish and Arab states in May 1948 when the British mandate was scheduled to end. As the time came nearer for Britain's mandate in favor of the Palestinian Arabs to cease, tensions rose for the Arabs against the Jews. The UN was very afraid of the chance of an all out war occurring between the two groups. Despite growing conflict between Palestinian Arabs, Palestinian Jews, and Department of State’s endorsement of a trusteeship, Truman ultimately decided to recognize the state Israel.

United Nations Partition Plan and Civil War

http://www.tlaxcala-int.org/article.asp?reference=8661
http://www.1948.org.uk/un-resolution-181/
https://history.state.gov/milestones/1945-1952/creation-israel