It is oversimplistic to say the Islamic Revolution was a response to that, because the Shah was already gone when Khomeini returned from exile. Rather, the gene

It is oversimplistic to say the Islamic Revolution was a response to that, because the Shah was already gone when Khomeini returned from exile. Rather, the general Iranian Revolution (with its heavy involvement of Communists and other secular movements) was a response to the Shah's dictatorship, and then the subsequent Islamic Revolution was a taking advantage of the resultant power vacuum.