After the British-American sponsored coup d'etat against Mossadegh, the Shah assumed dictatorial powers and outlawed almost all political groups, including Mellat Iran and the National Front. The Pan-Iranist Party soon became the official opposition in the Majlis, with Pezeshkpour as Speaker. However, in reality, the party had very little political power and influence and its position was primarily intended to be symbolic. Beginning in the late 1960s, under the government of Amir Abbas Hoveyda, Iran mostly became a one-party dictatorship under the Imperial Resurrection Party ("Rastakhiz").