Close to 50 heads of state are gathering in Washington for this week’s US-Africa Leaders Summit on the theme of “Investing in the Next Generation”. Among those being feted by American politicians, businesses and investors will be a handful of older strongmen, including the world’s longest-serving non-royal head of state, Teodoro Obiang Nguema Mbasogo, president of Equatorial Guinea.

The US has a history of courting many African strongmen, memorably Egypt’s Hosni Mubarak, Libya’s Muammer Gaddafi, Charles Taylor of Liberia and Zaire’s Mobutu Sese Seko. It is impossible to find an instance where turning a blind eye to corruption and human rights abuses has paid off for the US or Africa in the long run.

While Mr Obiang is in Washington, back home they commemorate the anniversary of the coup that brought him to power. In August 1979, he seized control from his uncle and mentor, President Francisco Macías Nguema, who used to hang dissidents from the capital’s few street lamps. A month later, he had Macías executed by firing squad.