Diefenbaker seldom backed down on matters he considered moral imperatives. In 1961, the Diefenbaker government stood with its Asian and African counterparts in condemning apartheid and formally opposing the renewal of South Africa's membership in the Commonwealth. Ultimately, rather than face the judgment of member states, South Africa withdrew its application for readmission into the Commonwealth of Nations.

"Apartheid has become the world’s symbol of discrimination. I took the position that if we were to accept South Africa’s request [for readmission] unconditionally, our action would be taken as approval or at least condonation of racial policies, which are repugnant to and unequivocally abhorred and condemned by Canadians as a whole."

(House of Commons, 17 March 1961)