 Complete the following phrase:  By November 1987, Castro began spending more time on the Angolan Civil War, in which the Marxists had fallen into retreat. Angolan President José Eduardo dos Santos successfully appealed for more Cuban troops, with Castro later admitting that he devoted more time to Angola than to the domestic situation, believing that a victory would lead to the collapse of apartheid. Gorbachev called for a negotiated end to the conflict and in 1988 organized a quadripartite talks between the USSR, U.S., Cuba and South Africa; they agreed that all foreign troops would pull out of Angola. Castro was angered by Gorbachevs approach, believing that he was abandoning the plight of the worlds poor in favour of détente. In Eastern Europe, socialist governments fell to capitalist reformers between 1989 and 1991 and many western observers expected the same in Cuba. Increasingly isolated, Cuba improved relations with Manuel Noriegas right-wing government in Panama  despite Castros personal hatred of Noriega  but it was overthrown in a 