Musa Kaz1m Efendi was Seyh-ul-islam six times in the Second Constitutional Period (1908-1919) of the Ottoman Empire and a member of the "Great Scientific Council" established by the Committee of Union and Progress (CUP). Between the years 1895 and 1918 he published many articles in journals and newspapers, as well as making speeches at the Sehzadeba~z Club of the CUP. As a medrese scholar in the years 1893-1908, he wrote within the intellectual tradition of Islamic Modernism, expressing views in line with those of the Young Ottoman thinkers of the 1860s and 1870s, defending Islam as a source of civilization and progress. He accepted the need for reform to match the material progress of the West, but argued that for this too Islam could be the source. The traditional side of his attitudes perhaps most reveals itself in his writings on the subject of women. After the beginning of the Second Constitutional Period, the nature of his writings underwent a subtle change when he chose to cooperate with the Committee of Union and Progress. Many of the members of the CUP regarded Islam unfavorably or, at best, as a means of popularizing policies, of winning over the ulema and of creating social stability. Musa Kaz1m Efendi's writings of this period, while still claiming Islam as a positive force and as the basis for reforms, were directed towards justifying the policies of the CUP, even where these policies tended towards secularization. Musa Kaz1m's career showed that members of the ulema could obtain office and a voice within the new constitutional regime, but whether such a solution favored the objectives oflslamic Modernists is more doubtful.