This article analyses the conflict in the 1950s between L.J. Du Plessis of Potchefstroom University and the South African prime minister, Hendrik Verwoerd. The issue was whether apartheid, in the way Verwoerd implemented it, was justifiable. Du Plessis came to the conclusion that apartheid would only be justifiable if it gave Africans a chance to realise their self-determination. Driven by his Calvinist convictions and inspired by the decolonisation process on the African continent, he argued for negotiations with South Africa's black political leaders, including those of the ANC. The Calvinist doctrine of justification explains why Du Plessis, who was a member of the Ossewabrandwag Grootraad during the 1940s, advocated dialogue with Africans. As a fervent cultural nationalist he believed in communities; he rejected individualism and parliamentary democracy. But when his conviction grew that time was running out for white South Africans, he was prepared to give up on apartheid as a policy. The National Party and Verwoerd rejected his proposals out of hand. Du Plessis was ostracised and expelled from the party. In the end, he became disillusioned and decided to resign from the Afrikaner Broederbond, whose chairman he had once been.