The dispute between the governments of Guatemala and Belize stemmed from opposing interpretations of an 1859 treaty signed by the Guatemalan administration and the UK, in which Guatemala recognised the sovereignty of British Honduras (as Belize was formerly known). In the aftermath of the Second World War, the Government of Guatemala argued that the British had reneged on certain clauses of the treaty, making it invalid, and therefore British Honduras was in fact a province of Guatemala.1 Tensions flared many times in the ensuing decades, most notably in 1982, when Argentina and the UK went to war following the occupation of the Falkland Islands. In 1991, Guatemala formally recognised Belize and the two states established diplomatic relations. Three years later, British forces left Belize after a lengthy operation to protect the sovereignty of its former colony.2 Seemingly resolved, the dispute escalated again in 1999 when the Government of Guatemala made fresh claims, based on historic treaties, on approximately half of Belizean territory. Hundreds of Guatemalan troops were deployed along the contested border, leading to several armed clashes between the armed forces of each state which brought them to the verge of war.3
In March 2000, the Organisation of American States (OAS) hosted representatives from Belize and Guatemala for negotiations in Washington, DC. In November, both sides signed the Agreement on Confidence Building Measures, which included the establishment of an “Adjacency Zone” which would separate the armed forces of each state by 2km.4 In 2003, the Guatemalan and Belizean foreign ministers signed the Agreement to Establish a Transition Process and Confidence-Building Measures.5 One such measure was the deployment of an OAS Office in the Adjacency Zone to oversee the implementation of confidence-building measures, monitor activities in the Zone, and facilitate dialogue.6 In addition, a “Group of Friends” consisting of significant regional and international governments was formed to support the OAS effort to prevent an armed conflict. These mechanisms served to calm the immediate crisis and prevent a war. On 8 December 2008, both governments agreed to settle the dispute at the International Court of Justice (ICJ) should the populations of both states approve such a course in referenda. Despite some minor clashes, war was prevented, the border has remained peaceful since the OAS diplomatic intervention in 2000, and both populations approved taking the dispute to the ICJ in referenda held in 2018-2019.7