Rhodesia declared its independence from Great Britain, in defiance of the British government. Rhodesia's government, led by Ian Smith, was all white in a country that was overwhelmingly black. Great Britain declared the act treasonable and immediately applied economic sanctions that were expanded by the United Nations.
Rhodesia was initially a British colony, part of the broader Federation of Rhodesia and Nyasaland, which also included modern-day Zambia and Malawi. By the early 1960s, decolonization was sweeping across Africa, with various territories gaining independence. However, in Rhodesia, a large number of white settlers had established themselves, particularly in fertile agricultural areas. The political and economic power was disproportionately in the hands of this white minority, who were reluctant to give up their privileges and allow for a transition to majority rule.
Ian Smith, who became Prime Minister in 1964, led Rhodesia's government at the time of the Unilateral Decleration of Independence. He was an ardent supporter of white minority rule and opposed any immediate move towards black majority governance. The all-white government's decision to unilaterally declare independence was seen as an attempt to perpetuate white supremacy in a nation where the overwhelming majority of the population was black.
Great Britain declared Rhodesia's decleration as treasonable and unconstitutional. The international community largely sided with the UK, leading to a series of economic sanctions against Rhodesia. The United Nations expanded these sanctions in 1968 to include virtually all forms of trade and financial transactions. These measures aimed to cripple Rhodesia's economy and force the government to negotiate a peaceful transition to majority rule. However, the sanctions were not entirely effective, partly because they were not universally adhered to. Some countries, particularly South Africa and Portugal (which still controlled Mozambique), continued to trade with Rhodesia, somewhat mitigating the impact of the sanctions.
Soon a prolonged armed conflict within Rhodesia developed , often referred to as the "Bush War." Various African nationalist groups, most notably the Zimbabwe African National Union (ZANU) and the Zimbabwe African People's Union (ZAPU), took up arms against the government. It wasn't until the late 1970s that a combination of internal pressures and international isolation forced the Rhodesian government to negotiate.