> Europe had long pressed Libya to help curb such migration. Muammar Qaddafi, Libya’s leader, had once embraced Pan-Africanism and encouraged sub-Saharan Africans to serve in the country’s oil fields. But in 2008 he signed a “friendship treaty” with Silvio Berlusconi, the Italian Prime Minister, that committed him to implementing strict controls. Qaddafi sometimes used this as a bargaining chip: he threatened, in 2010, that if the E.U. did not send him more than six billion dollars a year in aid money he would “turn Europe Black.” In 2011, Qaddafi was toppled and killed in an insurrection sparked by the Arab Spring and supported by a U.S.-led invasion. Afterward, Libya descended into chaos.