It is not every day that Kenneth Kaunda picked up the phone to call Nevers Mumba. Zambia’s founding president was a man of measured words and rare gestures, and so when the call came, it carried unusual weight. On the other end of the line, Kaunda did not exchange pleasantries. Instead, he warned Nevers that his name, alongside that of his own son Wezi, had surfaced on a secret government assassination list. More chilling still, he revealed the exact date the plot was meant to be carried out. Nevers’ two-year stint as vice president under Levy Mwanawasa ended abruptly after he was accused of claiming that the Congolese government was funding Zambia’s opposition, an allegation he flatly denies in his...