When his British passport was cancelled in the wake of Zimbabwe's independence in 1980, he was threatened with deportation and fought a protracted and highly publicized legal battle until 1983 when he was granted asylum in the United States. He continued to participate in protests against the apartheid government while teaching in the United States. He was eventually "unbanned" by the South African government in 1990 and in 1991 he became one of the sponsors of the Committee for Academic Freedom in Africa.