Ray Takeyh of National Review magazine wrote a great piece in 2021 reminding us of the original historical relationship with Iran. Some of the points to remember:
"The first thing that America did for Iran was to preserve its territorial integrity. The allies who had occupied Iran during the war [WW2] had agreed to withdraw their troops 6 months after the cessation of hostilities. Britain and America honored their pledge. Stalin [USSR] lingered in his occupation zone in the northern Iranian province of Azerbaijan and entrusted its management to the sadistic Lavrentiy Beria, the head of the NKVD, Russia's interior ministry and overseer of prison camps. Under the watchful eye of Russian soldiers, a puppet government calling itself the "Azerbaijan Democratic Party" was set up, and Beria's men created a secret police, which went on a killing spree, targeting Iranian army officers, police chiefs, local officials, and landed gentry. An area comprising the contemporary Republic of Azerbaijan was, like much of Eastern Europe, being carved out as a Soviet vassal state".
The USA dispatched the USS Missouri battleship fleet to Istanbul (Constantinople) and Stalin in the only time in the Cold War abandoned land held by his troops. America saved Iran from being carved by Stalin and the USSR. The USA provided Iran with billions of dollars in aid, technical assistance, and protection from the Soviet Union.
In August 1953 Iran experienced 2 coups. The removal of Prime Minister Mohammad Mossadegh was applauded by many iranians because he became a despot, rigging elections, disbanding the Parliament, usurping the existing powers of the monarchy, and showing little respect for their constitution. The CIA had some involvement in this removal. Yes before iran became an islamic totalitarian state they had a monarchy, a parliament, and a lively free press. A coup against the Shah had failed, however. Although the Shah had sought to modernize Iran, he progressively instituted centralized power in his office, becoming a quasi dictator. The Shah's regime collapsed quickly in 1978 due to economic stagnation, income inequality, and a revival of islamic fundamentalism and socialism, and islamic fundamentalists under the leadership of Ayatollah Khomeini took over. The Shah was not an American puppet, he had a mind of his own and no ideological support for democracy, and was overthrown by his own citizens. The USA continually tried to convince the Shad to develop democracy (political reform), develop social assistance programs, build up infrastructure, and promote economic freedom. The Shah accomplished some of this but not the critical political reforms to institute a true democracy.