Nelson Mandela

Optimism reigns as world leaders gavel a landmark climate deal at COP21.

When Nelson Mandela formed a National Unity government to rule the debut of a post-apartheid South Africa, he demonstrated both his magnanimity and his tactical sense, according to his late friend and chief of staff Jakes Gerwel.

Noah Davis talks to the democratic pollster and political strategist about the over-reliance on numbers, understanding new places, and being really intelligent.