While Ayatollah Khomeini was in exile in Najaf in 1970, he said:
This slogan of the separation of religion and politics and the demand that Islamic scholars not intervene in social and political affairs has been formulated and propagated by the imperialists; it is only the irreligious who repeat them. Were religion and politics separate in the time of the Prophet? Did there exist on one side a group of clerics, and opposite it, a group of politicians and leaders? (As cited by Nader Hashemi)
Violetta Zein mentions this letter, and the preceding events, at around 1 hour 24 minutes in her excellent youtube video:…