Briefly, uti possidetis juris is a principle, accepted by everyone as part of customary international law, that maintains existing territorial boundaries when a state achieves independence. Bell and Kontorovich argued that since Israel was the only state to emerge in 1948, and the international community never accepted that any other nation (Jordan and Egypt) held legal title on the West Bank and Gaza, that Israel held the best legal claims to those territories under international law unless it voluntarily gave those claims up.
While the argument sounds convincing, I am not a legal expert. As with other legal arguments given by Zionists and Israel - such as the argument that the League of Nations gave legal rights to the Jews of the entire territory of Palestine - I always wonder whether they hold water in the larger community of international law scholars. How much of these arguments are sound and how much of them only appears that way to me as a Zionist myself? After all, no one seems to have even considered applying uti possidetis juris to the disputed territories before 2016 even though hundreds of articles had been written on the topic of Israel's legal borders in the 49 years before Bell and Kontorovich's article.
In her dissenting opinion of the ICJ ruling saying Israel's "occupation" was "illegal," ICJ Vice President Julia Sebutinde of Uganda writes that uti possidetis juris is most definitely a factor - and, arguably, the factor - in determining who has legal rights over the territories.
70. Under international law there are several principles upon which legally enforceable borders are established, including effective control, historical title, and treaties. Uti possidetis juris is one of the main principles of customary international law intended to ensure stability, certainty and continuity in the demarcation of territorial boundaries of States emerging from decolonization or mandates such as the British Mandatory Palestine. In effect, the principle of uti possidetis juris transforms the colonial and administrative lines existing at the moment of birth of the new State into national borders. The principle applies to the State, as it is “at the moment of independence”, i.e. to the “photograph” of the territorial situation existing then. As the Court explained in the Burkina Faso/Republic of Mali case, the doctrine ensures that:“By becoming independent, [the] new State acquires sovereignty with the territorial base and boundaries left to it by the [administrative boundaries of the] colonial power . . . [The principle of uti possidetis juris] applies to the State as it is [at that moment of independence], i.e., to the ‘photograph’ of the territorial situation then existing. The principle of uti possidetis [juris] freezes the territorial title; it stops the clock."
...72. As stated above, when Britain terminated its stewardship over what was left of the Mandate for Palestine in 194777, according to the principle of uti possidetis juris, the administrative boundaries of the Mandate for Palestine on 14 May 1948 became the borders of the independent State of Israel (the only State to emerge from Mandatory Palestine at the time of Britain’s withdrawal)....73. Israel’s independence would thus appear to fall squarely within the bounds of circumstances that trigger the principle of uti possidetis juris. Applying the rule would appear to dictate that Israel’s borders are those of the Palestine Mandate that preceded it, except where otherwise agreed upon by Israel and its relevant neighbours. Indeed, Israel’s peace treaties with neighbouring States to date — with Egypt and Jordan — appear to reinforce it. These treaties ratify borders between Israel and its neighbours explicitly based on the boundaries of the British Mandate of Palestine. Likewise, in demarcating the so-called “Blue Line” between Israel and Lebanon in 2000, the United Nations Secretary General relied upon the boundaries of the British Mandate of Palestine79. Given the location of the borders of the Mandate of Palestine, applying the doctrine of uti possidetis juris to Israel would mean that Israel has territorial sovereignty over all the disputed areas of Jerusalem, the West Bank, and Gaza, except to the degree that Israel has voluntarily yielded sovereignty since its independence. This conclusion stands in opposition to the widely espoused position that international law gives Israel little or no sovereign claim to these areas
By using the argument of uti possidetis juris in her dissent, Sebutinde has elevated it in respect to determining the legal borders of Israel. The argument has been largely ignored since the publication of the paper, but Sebutinde ensures that it is now part of the conversation. And there is nothing on the ICJ website that disagrees with it.
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I can only find one serious objection to this argument, written by Ariel Zemach in Fordham International Law Journal in 2019. where he argues that in this case (unlike every other of uti possidetis juris,) the Palestinian right to self-determination trumps the principle because they formed a majority of the population of British Mandate Palestine in 1948. I can see that this argument has emotional weight, but I do not see how it has legal weight; it is a sui generis situation so there is no other precedent for overriding uti possidetis juris with a different principle. (One can counter-argue that if it wasn't for British anti-Jewish policy, Jews could easily have been the majority of Palestine as they would have fled there from Europe during the Holocaust if they could have. Their rights to self-determination should not be limited by an arbitrary and antisemitic immigration policy that contradicted the League of Nations.)
And even Zemach concludes that the principle of self-determination has nothing to do with the legal determination of national borders. "The bulk of the international community recognizes a
Palestinian entitlement to the whole of the West Bank, but because of
the lack of Palestinian possession of this territory—a corollary of the
status of the West Bank as an occupied territory—such international
recognition carries no constitutive effect," he concludes. So while he might disagree with Sebutinde, he would also disagree with the majority ICJ claim that the entire West Bank is presumptively "Palestinian."
