He recalls the popular challenge now underway against Omar al-Bashir’s rule in Sudan; the deaths of Kofi Annan, the first African secretary General of UN, and Winnie Mandela, a flawed leader of the South African liberation movement; the highly positive emergence of the reform-minded Abiy Ahmed, the Ethiopian prime minister; and the international attention to Congolese surgeon Denis Mukwege, who won a Nobel Peace prize for his work with rape victims.

In the spring of 2010, after years of relative quiet in the South China Sea —the strategic body of water separating southeastern China from Southeast Asia, and including regions disputed by at least …