Direct negotiations between Chile and Argentina in 1977–1978

The direct negotiations between Chile and Argentina about the islands and maritime rights in Beagle conflict began after the Queen Elizabeth II of the United Kingdom announced on 2 May 1977 the judgement of the Beagle Channel Arbitration to the governments of both countries. The court ruled that the islands and all adjacent formations belonged to Chile. The direct negotiations finished with the Act of Montevideo on 9 January 1979, where both countries accept the papal mediation after Argentina's call off of the Operation Soberanía. This was the most dangerous phase of the Beagle Conflict and there was a real possibility of open warfare.

Argentina and Chile were both ruled by military governments at the time of the negotiations. The Chilean and Argentine governments shared common interests: internal war against subversion, annihilating the opposition; external war against communism, remaining nonetheless part of the non-aligned movement; modernisation and liberalisation of the economy; a conservative approach towards social and class relations. By the end of 1977, the war against subversion and opposition was substantially over in both countries, as the Operation Condor had lost momentum and détente had improved East-West relations. The two countries maintained good economic relations.

But in 1977, the conflict over the Beagle Channel had become the primary foreign policy imperative of both governments.

There was considerable international condemnation of the Chilean Military Regime's human rights record. President Augusto Pinochet enjoyed absolute authority and was largely unaccountable to other elements within the military, the Beagle conflict was a less significant issue and there was a highly unusual dialogue on the subject with the opposition. Eduardo Frei Montalva, leader of the Opposition, backed the policy of the government in this matter:

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