Herds of African immigrants are being housed in shelters in the Mexican border town of Tijuana while they await entry into the United States under what appears to be a secret accord between the Obama administration, Mexico and the Central American countries the Africans transited on their journey north. A backlog of African migrants is overwhelming limited shelter space in Tijuana and Mexican officials blame the slow pace of U.S. immigration authorities in the San Isidro port of entry for granting only 50 asylum solicitations daily. Details about this disturbing program come from Mexico’s immigration agency, Instituto Nacional de Migracion...