Saudi Arabia is almost unique in giving the ulema (the body of Islamic religious leaders and jurists) a direct role in government. The preferred ulema are of the Salafi persuasion. The ulema have also been a key influence in major government decisions, for example the imposition of the oil embargo in 1973 and the invitation to foreign troops to Saudi Arabia in 1990. In addition, they have had a major role in the judicial and education systems and a monopoly of authority in the sphere of religious and social morals.