With the election in Iran and Obama's recent remarks about US involvement in the overthrow of Mossadeq in 1953, I thought I would transcribe a bit of history on the subject by Vali Nasr, which helps explain why Islam is so political in Iran today:
‘In Iran, the twentieth century saw the old partnership of kings and clerics strained to the breaking point. In 1925 the Shia ulama - Haeri’s father prominent among them - persuaded an army officer named Reza Khan, who had staged a coup, to declare himself shah. They feared the rise of a Kemalist ruler, and believed that whatever the faults of a Shia monarchy, it would be preferable to an aggressively secular republic of the sort that Mustafa Kemal Ataturk was building next door in Turkey. But the clerics got more than they bargained for, since the Pahlavi monarchy that Reza Khan founded turned out to have less to do with preserving Shiism than with acting as a modernizing republic parading in royal trappings. The Pahlavis never conceived of Iran as a Shia realm and refused to see defending Shiism as their duty. On the contrary, they perceived Shiism as a stumbling block to their modernizing agenda.
Before the first Pahlavi shah took the throne, he had taken part in Ashoura, beating his chest while calling out to Imam Husayn. The shah included the name of the eighth imam, Reza, which he also carried, in every one of his sons’ names. Nevertheless, he saw a Turkish-style secular state as vital to Iran’s modernization. Reza Shah secularized the legal system and the courts, banned the veiling of women, deemphasized Iran’s Shia identify, and marginalized the ulama - when need be, brutally. The ulama resisted - at times violently - but the combination of a powerful government and a modernizing society caused clerical influence to fade.
One area where the ulama could still make their weight felt was the struggle against imperialism. Clerics supported both the nationalization of Iran’s oil industry in 1951 and the popular movement that it created. The nationalization led to a confrontation between Iran and the West, which ended in 1953 with the CIA-backed military coup that ousted the nationalist premier, Muhammad Mossadeq, and restored power to the young shah, Muhammad Reza Pahlavi, who was Reza Shah’s son. While many in the Shia ulama supported Mossadeq’s goals, at the end of the day the most senior clerics backed the restoration of the monarchy because they badly feared chaos and a communist takeover. They set aside their sympathy for the nationalist cause and reacted to the same fears that led the US to support the coup. They had made, thought top clerics, yet another hard choice in order to defend the realm of the true (Shia) faith.
Whatever they meant at the time, however, the events of the early 1950s did not signal the birth of a lasting rapprochement between the throne and the Shia clergy. On the contrary, the 1960s and 1970s saw the state of relations between the two hit a new low. Rapid socioeconomic development, political repression, the growing influence of Western culture, the close ties between Tehran and Washington, and a growing gap between rich and poor all fed worsening social tensions. The ulama read these signs of the times as cause for worry, but also as an opportunity to undercut the religiously wayward Pahlavi monarchy. Some among the ulama also believed that unless Shiism took a leading role in the social and political struggles of the day, it would lose more ground and find itself shoved to the sidelines by leftists. To prevent this, the ulama would have to wax political as never before.’
--Vali Nasr, The Shia Revival