DrZoidberg
Contributor
Here's an excellent three part series (produced by Al-Jazeera) on the phenomena of the caliph. Even though it's made with the most careful language possible, it's pretty clear that it's a bullshit title of political convenience. The most powerful caliphs throughout history was the Ottoman caliphs and their claim to decendency from Mohammed is frankly absurd. As is ISIS' Al-Bhagdadi. So it's pretty clear that it's a meaningless term nowadays.
https://www.youtube.com/watch?v=P3O9d7PsI48
https://www.youtube.com/watch?v=P3O9d7PsI48