The Soviet Union did not, however, win support in the United Nations for its foreign policy positions. The Soviet Union and Third World states often argued that imperialism caused and continued to maintain the disparities in the world distribution of wealth. They disagreed, however, on the proper level of Soviet aid to the Third World. Also, the Soviet Union encountered fierce opposition to its invasion and occupation of Afghanistan and the Vietnamese occupation of Cambodia and received little support (as evidenced by Third World abstentions) for its 1987 proposal on the creation of a "Comprehensive System of International Peace and Security."