If you read the 1917 Balfour Declaration (Which emulated Napoleons 1799 letter to the Jewish community in Palestine promising that The National Home for The Jewish people - YJ Draiman

National Home for The Jewish people will be reestablished in Palestine

If you read the 1917 Balfour Declaration (Which emulated Napoleons 1799 letter to the Jewish community in Palestine promising that The National Home for The Jewish people will be reestablished in Palestine, as the Jews are the rightful owners). Nowhere does it state an Arab entity west of The Jordan Rive. The San Remo Conference of 1920 does not state an Arab entity west of The Jordan River. The Mandate for Palestine terms does not state an Arab entity west of the Jordan River. It specifically states a Jewish National Home in Palestine without limiting the Jewish territory in Palestine. It also states that the British should work with the Jewish Agency as the official representative of the Jews in Palestine to implement the National Home of the Jewish people in Palestine. I stress again; nowhere does it state that an Arab entity should be implemented west of the Jordan River. 
As a matter of historical record, The British reallocated over 77% of Jewish Palestine to the Arab-Palestinians in 1922 with specific borders and Jordan took over additional territory like the Gulf of Aqaba which was not part of the allocation to Jordan.

No where in any of the above stated agreements does it provides for an Arab entity west of the Jordan River. It specifically states political right to the Jewish people. The U.N. resolutions are non-binding with no legal standing.

YJ Draiman