According to Islamic tradition, the bay'a (translated as investiture or an oath of allegiance) is an act by which a certain number of persons, acting individually or collectively, recognize the authority of another person as the head of a Muslim state. This article analyzes the different modern political uses of the bay'a in the Arab world. Based on research of seven Arab case studies-the Kingdom of Hijaz, Iraq, Syria, Jordan, Egypt, Lebanon and Saudi Arabia, the article presents three arguments: First, the bay'a evolved into an elastic term politically used in a variety of ways by different Arab regimes. Second, the evoking of the bay'a ritual has often been a response to a domestic necessity or crisis. Finally, the use of this traditional ritual, along modern Western symbolic artifacts, is an indication of the evolving hybrid nature of the Arab political culture, based on a market of a mixed reservoir of foreign and local rituals and symbols. The interplay between foreign and local artifacts depends on the state's specific historical circumstances, which include also the impact of the colonial period. Ultimately, the modern uses of the bay'a demonstrate that modernity, in its Western version, has not been adopted wholesale. The bay'a ritual has been kept almost intact only in Saudi Arabia-a territory which did not go through the colonial experience. In contrast, Iraq, Syria and Jordan, which were under colonial rule, used an adapted version of this instrument on a temporary and utilitarian basis.