Nujoma became involved in politics in the early 1950s through trade unions. Nujoma's political outlook was shaped by his work experiences, his awareness of the contract labour system, and his increasing knowledge of the independence campaigns across Africa. In 1957, at age 29, Nujoma resigned from SAR so he could devote more time to politics. In 1957, a group of Namibians working in Cape Town led by Andimba Toivo ya Toivo formed the Ovamboland People's Congress (OPC). OPC was opposed to South African policies in South West Africa including the inhumane contract labour system under which people were forced to work for meagre wages. In 1958, ya Toivo sent a petition to the United Nations (UN) to force the apartheid regime to relinquish South West Africa to the Trusteeship Council of the United Nations. Consequently, he was expelled from Cape Town to Windhoek and then to Ovamboland where he was restricted. On 19 April 1959, Nujoma and OPC cofounder Jacob Kuhangua adapted a copy of the OPC constitution and formed the Ovamboland People's Organization (OPO) in Windhoek. At its first congress Nujoma was elected president. During the next year he travelled Namibia in secret mobilizing and setting up branch structures of OPO. In September 1959, the South West African National Union (SWANU) was formed as an umbrella body for anti-colonial resistance groups. Nujoma joined its executive committee representing OPO.