I was reading a book on the Italo-Turkish War that dwelt on the uneasy alliance between the Turkish military and local Mujahideen in what is now Libya against the common invader which had me wondering: how much of a problem did radical interpretations of Islam pose for the Ottoman Empire in its later stages?
Was a combative definition of religion a component of the nationalist movements in the Middle East and North Africa?
Thanks in advance!
It depends on what you mean by "Islamic radicalism." They had a problem with groups who's theology wasn't compatible with their's and posed an armed threat to the state. The two most important examples are:
The Qizilbash and other pro-Safavid Shi'i movements in Anatolia during the late 1400s and to mid 1500s were savagely put down Sultan Selim the Grim and his successors. People suspected of Safavid sympathies were deported to the ends of the empire, away from the Anatolian heartland, or banished entirely. However, these sympathies were never entirely destroyed, and in twist of history, some Qizilbash spiritual values were adopted by Ottoman's Janissary troops through their spiritual guides in the Bektashi Order (a twist because the Janissaries were the troops deployed by the Sultan to fight the Safavids and put down the Qizilbash within the empire).
The Wahabbi movement, with its base in Central Arabia (Nejd) and represented by the successive Saudi states, was combated by the Ottmans from the late 1700s through the end of the empire. During this long on-and-off war the Saudi-led Wahabbis actively fought the Ottomans and pillaged the main cities of the Arabia peninsula outside of Yemen and Oman, including Mecca and Medina. They also raided Ottoman territory in southern Iraq — including a particularly destructive raid on Karbala in 1808. The Ottomans asked the governor of autonomous Egypt to invade Arabia and put the rising down, which he did. The leader of the Saudi-Wahabbi state was sent to Istanbul and beheaded. The Ottomans combated the various incarnations of the Saudi state until the end of the empire in WWI. The last major loss of Ottoman territory to the Saudi state was eastern Arabia in 1913.
Source: Osman's Dream: The History of the Ottman Empire 1300-1923 by Caronline Finkel
A possible fit for your criteria of religious extremism in the Ottoman sphere is the 1880s Madhist War that ended the Turkiyah (turko-egyptian rule over sudan). Muhammad Ahmad declared himself Madhi (a messianic term), in opposition to the ottoman-loyal clerical establisment. I think it might be the kind of situation youre looking for; suprised it hasnt been mentioned already.
Admittedly, it's a bit of a stretch, as the Sublime Porte granted the Khedive (viceroy) of Egypt a lot of autonomy from Istanbul's governance. But it was still part of the Empire.
A scholar better than I can point you in the right direction, but in the meantime read Dominic Green's 'Victorian Jihad: Three Empires on the Nile'
*the mahdi term was used in the recent Iraq war by cleric Moktada al Sadr. Funfact!