The borders between Israel and Palestine have always been in dispute but there is no US policy of Israel ruling all of Palestine.
The borders between Israel and Palestinehave always been in dispute but the Green Line is the one that is US policy
The boundaries of the State of Israel have never been completely settled but there is no precedent for Israel ruling the whole of Palestine.
After World War I, the United Kingdom was given a mandate for Palestine, which it had conquered from the Ottomans during the war. In 1937 the Peel Commission suggested partitioning Mandate Palestine into an Arab state and a Jewish state, though the proposal was rejected as unworkable by the UK government.
His Majesty’s government view with favour the establishment in Palestine of a national home for the Jewish people, and will use their best endeavours to facilitate the achievement of this object, it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine, or the rights and political status enjoyed by Jews in any other country.
UK ruled Palestine through the end of World War II, when it gave up its “mandate”. It left the new United Nations to partition Palestine into a Jewish and Palestinian states. On November 29 1947 the UN Resolution 181(II) provided:
Independent Arab and Jewish States and the Special International Regime for the City of Jerusalem, … shall come into existence in Palestine two months after the evacuation of the armed forces of the mandatory Power has been completed but in any case not later than 1 October 1948.
The UN resolution and in particular the borders drawn by the UN were never accepted by either side. A Jewish/Palestinian civil war ensued, which ended in a cease fire (“1949 armistice) and “armistice lines”, which left Israel with 50% more land than included in the 1948 UN resolution.
In a December 1969 speech, Nixon’s US Secretary of State William P. Rogers said that any changes in the pre-existing [1949 armistice] lines should not reflect the weight of conquest and should be confined to insubstantial alterations required for mutual security. We do not support expansionism.
The “1949 armistice lines” are what is widely known as the “pre-1967 borders” and the “Green Line” (named after the color of ink that was used to draw the armistice line on a map). The 1949 armistice lines gained wide de facto recognition the existence of 1) the State of Israel and (2) Palestine. That is, previous disputes have all been about the exact borders of two states. The US foreign policy for the 70 years since Israel was created contemplated two states between the sea and the Jordan rivers.
President Obama recently reaffirmed the US policy:
The United States believes that negotiations should result in two states, with permanent Palestinian borders with Israel, Jordan, and Egypt, and permanent Israeli borders with Palestine, Obama said in the concluding section of his 45-minute address that looked at political and social change sweeping across the Middle East and North Africa.
We believe the borders of Israel and Palestine should be based on the 1967 lines with mutually agreed swaps, so that secure and recognized borders are established for both states.
So far there is no US policy that contemplates Israel annexing all of Palestine within the State of Israel.