Before the two constitutions, the Ottoman Sultan was an absolute monarch along with being the Caliph. With the constitutional monarchy in place, how exactly could the Ottoman Parliament stop the Sultan from exercising his powers as Caliph to overrule them?
The first Ottoman Constitution came in wake of an era of reforms known as the Tanzimat - literally meaning "reorganization"- which was marked by indiscriminate adoption of Western social and political practices. The politicians and intellectuals who elaborated the Fundamental Law of 1876-known as the Young Ottomans- rejected the notion of simply copying the Western traditions and believed that the best principles of reformation lay in the Islam tradition. Thus, the notion of an assembly that could keep in check the power of the sultan and his ministers actually has it's root in the old precepts of Islam. When Abdul Hamid II came to power in 1876, the Young Ottomans saw the chance to impose their law- to which the new sultan allegedly agreed, that is, if certain of his demands were met. According to the Constitution the sultan retained full executive power while the legislative power was given to a two chamber Parliament (the lower house was indirectly elected while the upper house was nominated by the sultan). The Constitution also proclaimed the principle of individual ministerial responsibility. In theory, the 1876 Constitution of the Ottoman Empire meets the requirements of a modern, organized fundamental law. In practice, you could argue that established system was a toned-down version of an autocracy, thanks to the amendments demanded by Abdülhamid, including the then-notorious article 113, which gave the sultan the right to deport persons harmful to the state. That being said, the Sultan’s powers did not grow any weaker under the Constitution, which he abolished after only two years.