What is the function of political parties in authoritarian regimes where they cannot contest the highest executive office? How do parties in such regimes build memberships, address constituencies, and compete with each other? What constitutes political party strength in such regimes? How is such strength measured? This paper seeks to answer these questions through studying the formation and evolution of two political parties in Morocco, Istiqlal and the Party of Justice and Development (PJD). The existing theoretical literature on political parties in authoritarian regimes does not satisfactorily address these questions. Most of this literature focuses on hegemonic parties in single-party or hegemonic-party regimes. Hence, its theoretical propositions do not travel to authoritarian regimes where there is no single, dominant party. The existing literature on political parties in the Arab World also does not provide sufficient answers. Often placing authoritarian incumbents at the center of the analysis, this literature considers party outcomes as functions of authoritarian manipulation. Morocco is an ideal setting for answering the above research questions, as ultimate executive power lies in the hands of the monarch yet there is a vibrant political party scene. The paper examines episodic political party competition and variation over time in competition trends, studying the development of Istiqlal and PDD from 1944-2013. The dependent variable of the study is the political relevance/strength of Istiqlal and PJD. I conceptualize party strength as the quality and quantity of attention afforded to political party cadres in national and foreign media coverage on Morocco, interviews and archival documents. The methodology consists of in-depth content analysis of Moroccan and foreign media sources, supplemented by interviews of Moroccan diplomats / diaspora in Washington, DC and archival research of diplomatic communiques and other primary sources in the National Archive and the Library of Congress. There are both theoretical and empirical reasons to pursue this study. To date, political science research has not theorized the behavior of parties in authoritarian regimes where they cannot gain executive power. The literature has also not yet contributed an effective way of measuring political party strength in authoritarian regimes. Empirically, studying political party behavior in authoritarian settings can help understand the political vacuum characterizing a post-revolutionary Arab world today. Hence this study can contribute important findings to the scholarship on Arab political participation and prospects for democratization.