Now, Truman wasn't at first favorable to voting for UN resolution, but he was persuaded by a close Jewish friend of his. This doesn't suggest to me that it's an US foreign policy which is supporting the establishment of a Jewish state as much as a President signing on to resolution which results in the legalizing of the "establishment of a state". Now, you may say this is nitpicking. But my point is for Truman this was relatively easy- he wasn't commiting the US to some strategic interest- though that did occur, but it was a decade or so later [as I said we did get dragged into it].

What makes you think President Truman wasn't in favor of the UN resolution at first? This is from a chronology of the U.S. involvement in the establishment of Israel:

October 4, 1946: On the eve of Yom Kippur, President Truman issues a statement indicating United States support for the creation of a "viable Jewish state."

October 28, 1946: President Truman writes to King Saud of Saudi Arabia, informing the king that he believes "that a national home for the Jewish people should be established in Palestine."

August 31, 1947: The United Nations Special Committee on Palestine issues its report, which recommends unanimously (all 11 member states voting in favor) that Great Britain terminate their mandate for Palestine and grant it independence at the earliest possible date; and which also recommends by majority vote (7 of the member nations voting in favor) that Palestine be partitioned into Jewish and Arab states.

October 11, 1947: Herschel Johnson, United States deputy representative on the United Nations Security Council, announces United States support for the partition plan of the United Nations Special Committee on Palestine.

November 29, 1947: The United Nations General Assembly approves the partition plan for Palestine put forward by the United Nations Special Committee on Palestine. The 1947 UN Partition divided the area into three entities: a Jewish state, an Arab state, and an international zone around Jerusalem.

If you believe the account of Jacobson (and I see no reason not to), Truman played an important role in the passing of the 1947 UN resolution for partitioning. Saying Truman was merely "signing on" doesn't accurately represent his efforts or his influence. As lthe world's only nuclear superpower at the time, the U.S. had a great deal of influence in the international community, (which is why Ho Chi Minh tried desperately to get the U.S. to officially recognize the Democratic Republic of Vietnam). As Weizmann said, the fate of Israeli statehood was in Truman's hands.

As for it being "relatively easy" for Truman, his Secretary of State, George Marshall, probably the most popular man in America at the time, was adamantly against the U.S. supporting Israel's statehood, as were the Joint Chiefs of Staff. According to them, Truman was turning his back on U.S. stategic interests, alienating the oil-producing Arab countries and pushing them into the arms of the Soviets.

After the U.S recognized Israel, Marshall sent an official to the UN to talk the entire U.S. delegation out of resigning.

Israel became a nation of May 14, 1948. On May 15, Egypt, Syria, Jordan, Lebanon and Iraq attacked. Hard to imagine Truman wouldn't have seen that coming.

Believing that Truman supported Israel statehood on the advice of a friend or that it was relatively easy for him is a misreading of history.