The principle criterion is that petroleum must constitute the main source of the applicant state's national income. Later it was realized that such a condition was highly selective and would restrict the membership of the organization to some, rather than most, of the Arab countries. This was not in harmony with the basic objective of the organization; that is, greater co-operation between all Arab states. Consequently the Saudi government suggested an amendment to Article 7 whereby any Arab petroleum exporting country in which petroleum represents an important (rather than the main) source of income may join.
