12 August 1952
Walter Sisulu joined the ANC in 1940. He was elected to the executive committee of the ANC Youth League in 1944 and in 1949, was instrumental in the ANC's adoption of the Youth League's Program of Action. In the same year, he was elected as ANC Secretary General. With the National Party victory in 1948 came the official implementation of apartheid. Repressive laws were soon introduced with a proposal to ban the Communist Party (CPSA).  This led to the formation of the Congress Alliance, of which Walter Sisulu and Yusuf Cachalia were appointed joint secretaries. A national work stoppage was organised for 26 June 1950 to protest against the newly-implemented apartheid laws. Walter Sisulu played a significant role in the planning of the 1952 Defiance Campaign in which over 8 500 volunteers were mobilised to contravene apartheid laws. On 12 August 1952, Sisulu was arrested, and consequently banned under the Suppression of Communism Act. Later that year Sisulu, Nelson Mandela, James Moroka were tried for their involvement in the Defiance Campaign. All accused were sentenced to nine months' imprisonment with hard labour. Although banning orders prevented him from attending political meetings and addressing gatherings, Walter Sisulu continued to work secretly for the ANC. He was accused of treason in the 1956 Treason Trial and following his arrest for acts of sabotage committed as part of Umkhonto we Sizwe, was sentenced to life imprisonment in the Rivonia Trial. Released in 1989, Walter Sisulu remained active in politics until 1994. Related: Rivonia Trial Reunion held
References

Nelson mandela Centre of memory, "The Suppression of Communism Act",from Nelson mandela Centre of memory [Online], available at www.nelsonmandela.org [Accessed: 08 August 2013]|

moreorless,(2001), "Walter Sisulu", from moreorless, 27 January [Online], available at www.moreorless.au.com [Accessed: 08 August 2013]