It has been established elsewhere that gaining the Caliphate for the Hāshimite family was a consuming interest for the Sharīf of Mecca, ῌusayn b. ‘Ali, and his son ‘Abdallāh. The  desire  to  take the Caliphate  played a  cardinal  role  in  his  decision  to  revolt against the  Ottomans. As ῌusayn would have it, he was revolting not to establish a kingdom in the ῌidjāz, and not simply a large Arab state, but to establish a replacement Islamic polity, in which the Arabs, led by the Hāshimites, would take their rightful place.

Full Text: ’Taking Back’ the Caliphate: Sharif Husayn ibn `Ali, Mustafa Kemal, and the Ottoman Caliphate,” Die Welt Des Islams, Vol. 40 (November 2000), pp. 412-424.