West New Guinea dispute

The West New Guinea dispute (1950–1962), also known as the West Irian dispute, was a diplomatic and political conflict between the Netherlands and Indonesia over the territory of Dutch New Guinea. While the Netherlands had ceded sovereignty over most of the Dutch East Indies to Indonesia on 27 December 1949 following an independence struggle, it retained control over its colony on the western half of New Guinea. The Indonesian government claimed this territory as well, on the basis that it had belonged to the Dutch East Indies and that the new Republic of Indonesia was the legitimate successor to the former Dutch colony.

During the first phase of the dispute (1950–1954), Indonesia pursued bilateral negotiations with the Netherlands. During the second phase (1954–1958), Indonesia attempted to raise support for its territorial claims in the United Nations General Assembly. During the third phase (1960–1962), Indonesia pursued a policy of confrontation against the Netherlands which combined diplomatic, political, and economic pressure with limited military force. The final stage of the confrontation with Indonesia also involved a planned military invasion of the territory. The Indonesians also secured military weapons and political and military support from the Soviet Union, which induced the United States to intervene in the conflict as a third-party mediator between Indonesia and the Netherlands. Following the New York Agreement on 15 August 1962, the Netherlands, under U.S. pressure, handed West New Guinea over to a United Nations Temporary Executive Authority, which subsequently handed the territory over to Indonesia on 1 May 1963. Following a controversial plebiscite in 1969, West New Guinea was formally integrated into Indonesia.