South Africa is one of Africa's most liberal outposts, while Kenya has a reputation for conservatism. But no society is static, least of all in Africa. And the recent appointment processes around new chief justices in these two regional powerhouses demonstrates just how important – and potentially vulnerable – the democratic rule of law is, in places that have long histories of human rights abuse, and where inevitable social change threatens age-old customs. An opinion piece by Mark Gevisser for The Guardian.