The principle of uti possidetis juris could, in theory, be considered in relation to the boundaries of the British Mandate for Palestine as they existed at its termination in 1948. However, its application is highly debated and not straightforward. Here’s how the argument could be structured, along with the legal and political complexities:

1. The British Mandate’s Boundaries

• The British Mandate for Palestine was defined by the League of Nations in 1922, with borders that included:
  • Modern-day Israel
  • The West Bank
  • The Gaza Strip
  • Transjordan (which became the independent state of Jordan in 1946)
• The Mandate’s eastern boundary was the Jordan River, and its southern boundary extended to the Red Sea.

2. Applying Uti Possidetis Juris to the Mandate’s Limits

Theoretical Application: If uti possidetis juris were applied, the borders of any successor states emerging from the Mandate would be based on the administrative boundaries of the Mandate at the time of its termination (May 14, 1948). This would mean the entire Mandate territory (excluding Transjordan, which had already become independent) would be the starting point for determining the borders of new states.

Implications:

• The West Bank and Gaza would be part of the territory of a new state (or states) emerging from the Mandate.
• Israel’s borders would theoretically be limited to the Mandate’s boundaries, unless modified by agreement or conflict.

3. Why This Is Controversial

No Direct Succession: The Mandate did not end with the creation of a single successor state. Instead, the UN proposed a partition (Resolution 181) that was rejected by Arab leaders and never implemented. The 1948 Arab-Israeli War resulted in de facto borders (the "Green Line") that did not match the Mandate’s boundaries.

Transjordan’s Independence: Transjordan (modern Jordan) had already become independent in 1946, so the Mandate’s eastern boundary was no longer relevant to the 1948 partition.

UN Partition Plan Overrode Mandate Borders: The UN’s 1947 Partition Plan proposed new borders that did not align with the Mandate’s boundaries. While the plan was never fully implemented, it set a precedent for negotiating borders rather than defaulting to the Mandate’s limits.

1949 Armistice Lines: After the 1948 war, the Armistice Agreements established the "Green Line," which became the de facto border between Israel and the West Bank (then under Jordanian control). These lines were not based on the Mandate’s boundaries.

4. Legal and Political Reality

Uti Possidetis Juris in Practice: The principle is typically applied to administrative units within a colony or empire, not to the external borders of a Mandate. The Mandate for Palestine was a unique legal construct, not a traditional colony, and its borders were not designed to become the borders of a future state.

International Law and Occupation: Since 1967, the West Bank has been considered occupied territory under international law (Fourth Geneva Convention). The focus has been on the laws of occupation and the right of self-determination for Palestinians, not on the Mandate’s historical borders.

Modern Claims: Some arguments for a "Greater Israel" or "Eretz Israel" refer to the Mandate’s borders as the historical limits of the Jewish homeland. However, these claims are political and not recognized under international law.

5. Summary Table

Conclusion

While uti possidetis juris could theoretically be invoked to argue that the Mandate’s borders should have defined the limits of successor states, this was not the path taken in 1948. The UN Partition Plan, the 1948 war, and subsequent armistice agreements created a new legal and territorial reality. Today, the West Bank’s status is governed by the laws of occupation and the framework of a two-state solution, not by the Mandate’s historical boundaries.

If you’d like to explore how this principle might apply to other historical cases or modern territorial disputes, let me know!