Original:  He believed that "constitutional form of government" would be the best possible choice in the absence of Imam and regarded the "Persian revolution" a Jihad ("holy war") in which all Muslims had to participate.
Revised:  He believed that "constitutional form of government" would be the best possible choice in the absence of Imam and regarded the constitutional revolution" a Jihad ("holy war") in which all Muslims had to participate.
Edit intent: meaning-changed