The effect of the security forces' decisive counter-campaign was undone by two drastic changes to the geopolitical situation in 1974 and 1975, each relating to one of the Rhodesian government's two main backers, Portugal and South Africa. In Lisbon, a military coup on 25 April 1974 replaced the right-wing "Estado Novo" administration with a leftist government opposed to the unpopular Colonial War in Angola, Mozambique and Portugal's other African territories. Following this coup, which became known as the Carnation Revolution, Portuguese leadership was hurriedly withdrawn from Lisbon's overseas territories, each of which was earmarked for an immediate handover to communist guerrillas. Brief, frenzied negotiations with FRELIMO in Mozambique preceded the country's independence on 25 June 1975; FRELIMO took power without contesting an election, while Samora Machel assumed the presidency. Now that Mozambique was under a friendly government, ZANLA could freely base themselves there with the full support of Machel and FRELIMO, with whom an alliance had already existed since the late 1960s. The Rhodesian Security Forces, on the other hand, now had a further of border to defend and had to rely on South Africa alone for imports.