From a widely-acknowledged classic, Palestine and the Arab-Israeli Conflict, by Charles D. Smith of the University of Arizona (1996).
As debate over the UNSCOP [UN Special Committee on Palestine] recommendations continued through November , it seemed clear to Zionists in the United States that extensive lobbying and pressure would have to be brought to bear on certain delegates. Truman remained on the sidelines until the eve of the vote, but he declared in his memoirs that he had never "had as much pressure and propaganda aimed at the White house as I had in this instance." Congressmen and senators along with Supreme Court justices were drafted to send telegrams to heads of states and their representatives either cajoling them, or in some cases, threatening suspension of American aid. On the day the vote was scheduled, 27 November, the partition resolution appeared to be short of the needed two-thirds majority. Filibustering gained a postponement [to November 29], and Truman approved further pressure on the delegates. Under threat of a Jewish boycott of Firestone rubber and tire products, Harvey Firestone told Liberia that he would recommend suspension of plans for the expansion of development there if Liberia voted against partition. Truman’s approval of added lobbying efforts may have saved the day, as until then he and the State Department seemed in accord: the United States would vote for partition but not threaten or lobby other members, leading the Arab officials to assume that they had won….Whatever the nature of the Zionist accomplishment in Palestine, the victory at the United Nations was essentially won in the United States where "the success of the Zionist effort in 1947 represented nearly five years of work, organization, publicity, education, and the careful cultivation of key people in different fields,… thus securing the help of influential men and women in the press, the church, the arts, and above all, the government. In the process, the plight of the displaced persons in Europe played an ever-present role." [quote from We Are One! American Jewry and Israel, by Melvin Urofsky] Amidst the wild celebrations in New York, Tel Aviv, and the Jewish sectors of Jerusalem, both Arabs and Jews prepared for war.