Taking advantage of the quiet, the CIA and its Iranian allies struck again, and on 19 August the coup d'état replaced Mosaddeq with Zahedi. The coup was a major event in Third World and 20th Century history and there is debate as to how much of the blame for the overthrow can be traced to bribes paid by the CIA and how much to domestic dissatisfaction with Mossadeq. Whatever the motivations, Mohammad Reza Pahlavi thereafter assumed dictatorial powers and banned most political groups, including Mossadegh's National Front, which along with the Tudeh Party, continued to function underground.