Suppose that:
After WW2 Britain and Iran negotiated a deal that was much more profitable to Iran. Prime Minister Haj Ali Razmara took it back to Iran's parliament where it was approved. Razmara had sought to provide benefits to the Iranian people, and to do this he took steps to eliminate the central bureaucracy, and restore power to the public at lower levels of decision making. With the benefit of the new AIOC agreement, Razmara encouraged the Shah to go ahead with reforms which turned into the 1953 White Revolution. This series of reforms synergized well with the Point IV assistance agreement Razmara had made with President Truman.

Razmara's efforts towards decentralization created a small basic income which helped to offset the problems associated with the Shah's upending of long standing agricultural labor practices. All things considered, the Tudeh Party and the National Front Party lost a lot of their momentum though this period of the 1950s. In March of 1951, while visiting the Shah Mosque, Razmara was also able to avoid the assassin's bullets. Working together closely with the Shah, Razmara cracked down on those Fedayeen-e-Islam who had been advocating for assassinations.

Though ineffectual, Iran expressed its commitment against the Soviet Union by joining the Baghdad Pact in 1955. Razmara resigned in 1956 to leave public life; he left the country with financial strength, and internal peace. Culturally, the Ayatollahs were becoming marginalized while an appreciation for western civilization was growing. Iraq would soon pose a problem with the fall of the Hashemite monarchy, otherwise there is no real foreign danger at that moment. The Shah had not had the strong impetus thus far to assume greater autocratic control of the country either.

What happens next?
 
Top