in 1981 chester crocker, u.s. assistant secretary of state for african affairs for newly elected united states president ronald reagan, had developed a linkage policy. it tied apartheid south africa's agreement to relinquish control of namibia, in line with united nations security council resolution 435, and to retreat from angola, to cuba's withdrawing its troops from angola. on 10 september 1986 cuban president fidel castro accepted crocker's proposal in principle. the south african government also accepted the principle of linkage; it proposed the concept at the un 7th plenary meeting on 20 september 1986 (the question of namibia).