Uti Possidetis, Ethnic Composition and Equity in 1921 Latvian-Lithuanian Border Arbitration

During their very first years of statehood, modern Latvia and Lithuania confronted the urgent need to determine the borderline between their territories. The way they resolved this issue through the recourse to international justice by arbitration formed a remarkable example of peaceful settlement of disputes. The award of the arbitration commission delivered one hundred years ago on 20 March 1921, contributed itself to the formation of the international rules on the delimitation of State boundaries.

This article explores the application of uti possidetis, defined as a principle of customary international law that serves to preserve the pre-existing boundaries of territories emerging as States, in the border dispute between Latvia and Lithuania, and the lessons learned after a century of that arbitration.

The dispute

The settlement of World War I at the Paris Peace Conference gave birth to nine new nations. Before the Conference opened in January 1919, the Russian and Austro-Hungarian empires had collapsed. Within these territories arose the States of Czechoslovakia, Estonia, Finland, Hungary, Latvia, Lithuania, Poland and Yugoslavia. The Treaty of Versailles created the conditions to establish new states. However, the major powers chose not to address the territorial limits between those states (with a few exceptions). These remained to be defined by the new nations themselves. Here, the basic choice was between the principle of territorial stability, i.e. application of the principle of uti possidetis, and the identification of the historical and ethnic limits of the new nation-states.

At that time the borderline between Latvia and Lithuania was rather uncertain. In 1819, the Lithuanian town Palanga with the entire coastline down to the Prussian border was added to Kurland gubernia. In many other places, the line between Czarist gubernias failed to represent the ethnic composition of the population.  On the contrary, independence was established “within ethnic boundaries” with reference to the exercise of the right to self-determination.

In 1919 the delegations agreed during bilateral consultations in Paris that the administrative border of Kurland and Kovno gubernias could be taken as the State border, provided that the Baltic coast up to Šventoji River would be given to Lithuania.  Unfortunately, this compromise was not approved by the capitals. Both parties backed their claims by reference to the ethnic composition of the population in the disputed areas. Moreover, economic factors also informed the positions of the two governments maintain their positions. Lithuania acknowledged the importance of its rights to the Palanga coast as its only access to the Baltic Sea. Access to the Daugava River through the Kalkuone railway line could also serve Lithuania’s economic interests. In turn, Latvians demanded Mažeikiai to ensure rail traffic from Liepaja port (Z. Butkus, 1993).

The situation was complicated by the fact that in fighting their enemies’ military forces from one state appeared to control substantive parts of the other state’s territory.  Failing bilateral consultations then, it became obvious by autumn 1920 that the two governments were unable to find a diplomatic solution to the frontier dispute by means of negotiation. The situation became dangerous as armed clashes were reported between the troops alongside the provisional control line.   The bilateral arbitration convention was signed in Riga on 28 September 1920 (Societé des Nations. Récueil des Traités, vol. 2 (1920–1921), p. 234). Contrary to a request for mediation or good offices, the compromis specified that the decisions of the arbitration commission shall be legally binding and “loyally accepted by both Governments” (Article 2). The parties also established several specific parameters for the decision: to take into account ethnographic and historical principles and the state-political interests of each party (military, strategical, economic and communicational) and the interests of the local population. This provision, in turn, repeated the preceding arbitration agreement between Latvia and Estonia.

Uti Possidetis line

Only an existing territorial unit, defined well enough, may claim independence; after all, it is a territorial group and not an ethnonational group that may be asked of its opinion through a plebiscite. The territorial solution of the principle of self-determination has been found in the general principle of international law of uti possidetis.

At the time of the dispute in question, the principle of uti possidetis was generally accepted as a binding international norm with regard to Latin America. The rule appeared in many constitutions of the American continent and in many inter-American treaties.

It may be argued, though, that this principle only applies to international boundaries, which, after all, are accepted as lines dividing sovereign entities with all that that implies. Internal boundaries are clearly not so established. The peoples of Latvia and Lithuania had no influence in drawing the line between the two Czarist gubernias which failed to correspond, in many places, to the historical and ethnical boundary between the two nations, as well as their economic needs. However, at the time of the accession to independence both countries were in favour of accepting the existing line with necessary adjustments.

Even though the existing territorial line of 1914 was not explicitly mentioned in the arbitration agreement, it appears clear from the minutes of the meetings and the award of the commission of 20 March 1921 that the administrative line between the Russian Kurland and Kovno gubernias was taken as a starting point for the delimitation of the Latvian and Lithuanian border. It is difficult to imagine, both from a practical and legal point of view, that a borderline between two States may be drawn without reference to any pre-existing boundary of whatever provenance. In our case, the two Republics actually controlled the territories of the respective gubernias, and their local authorities generally remained under continued subordination of the capitals, thus maintaining the territorial status quo. Denying this factual situation could have led to destabilization in the border areas and might have triggered the use of force from both sides.

Whether the former administrative boundary was accepted by practical reasons or as a legal principle of uti possidetis remains uncertain. Neither the correspondence nor the minutes or the ruling of the arbitrators mentions this principle. However, both delegations were asking for the adjustment of the old line, and the ruling mentions the portions of the land to be transferred as compared to the status quo: 29,999 hectares went to Latvia and 20,873 hectares to Lithuania.

It is important to mention that the arbitration commission gave no relevance to the fact of the presence of the armed forces beyond the former administrative line. Uti possidetis juris was thus preferred to uti possidetis facto in determining the actual frontier, even if the line was established as an internal boundary by legal acts of a third state.

The just ethnic composition 

The other two main principles applied in the award were ethnographical composition and equity. The new boundaries must reflect the views of the people concerned. As observed by Ratner in 1996 “when a new state is formed, its territory ought not to be irretrievably predetermined but should form an element in the goal of maximal internal determination”. In our case sub-commissions were established to investigate the national consciousness of the populations in the disputed areas; both delegations presented scientific studies concerning historical and ethnic origins of those living on both sides of the old administrative line, and those were carefully studied by the chairman of the tribunal and verified on the spot. However, the arbitral tribunal failed to resort to the plebiscites as referred to in the compromis. According to the President of the Commission, the decision to hold a plebiscite in one disputed area would lead to the demands of the loser to decide all the boundary on the basis of the sympathies of the voters, which was of neither party’s interest.

Three sections of the frontier were drawn by the commission on the basis of ethnic grounds, adjusting the frontier to separate the areas dominated either by Lithuanian or Latvian-speaking populations. On these grounds, Aknysta (Aknīste) region was given back to Latvia and the coastal town of Palanga to Lithuania. Concerning the third section of the frontier, the Commission found itself unable to confirm the Lithuanian claim that the ethnic composition of the population favoured the transfer of Ilūkste (Alūkšta) region or part of it to Lithuania.

It is clear from reading the decision and its commentary by Charlotte Alston of 2002 and Zenonas Butkus of 1993 equal outcome constituted the most important task of the Commission. The final result of the ruling provided for more or less similar portions of land for both parties. Despite the general principle to adjust the boundary on ethnic grounds, the report of the commission stresses that “to base its decision solely on the grounds of ethnographic majority in the light of the circumstances was to let the majority to take with it very disproportionate land plots”. Therefore, the intention of the commission was indeed to provide the parties with more or less equal land plots, which could eventually be used to settle the displaced ethnic population from the other side of the frontier.  Probably this was also one of the reasons not to resort to the plebiscites in the disputed areas. In his final evaluation of the work of the Commission, its President professor Simpson also notes that “it was impossible, as it would have been unwise, to attempt to apply any hard and fast rule all along the line”. Both Lithuania and Latvia were basing their claims on similar grounds. Disproportionality in adjusting the factual boundary may have had created problems of implementation of the award.

The principle of equity was largely applied in border delimitation at the beginning of the 20th century. For instance, the 1930 arbitration treaty between Guatemala and Honduras stipulated that in the case that either party has acquired interests beyond the uti possidetis line, they must be taken into consideration in establishing the final frontier, the arbitral tribunal shall modify as it may consider suitable the line and shall fix such territorial or other compensation as it may deem equitable for one party to pay to the other.

Final remarks

As prescribed by the compromis, the Commission took into account the ethnic origin of the majority of population in the disputed areas, economic needs of both countries (to certain extend). The main preoccupation however was not to find out the exact historical, ethnographic or economically justified line between the two countries but to settle their dispute by trying to find the compromise based on law and acceptable to both parties, and the solution was found in equitable delimitation of the disputed areas. Time has proven that Simpson was right when writing in the report of the commission that “adjustments have been made which are not without some value in many cases to both sides, and which may stand the test of time”. Legal principles applied by the arbitration commission in the 1921 Lithuanian-Latvian border dispute follow closely the classic border delimitation theory (see for example D.B. Carter, H.E. Goemans 2009), contributing to the remarkably stable line of state practice. Continuous application for 100 years since the successful settlement constitutes a significant indicator of the value of the award as important guidance for border arbitrators.


Rytis Satkauskas graduated from Vilnius University in 1999 and continued his doctorate studies in Paris (1999-2000) and Madrid (2003-2004). He lectured at the Vilnius University Law Faculty and publishes continuously on aspects of international humanitarian law, investment protection, border delimitation, law of the sea, minority rights and international justice. Rytis Satkauskas practiced public international law for more than 20 years within the Ministry of Foreign Affairs of Lithuania with diplomatic postings in Madrid, Paris, Beijing, and London.