How did the Iranian Revolution change Iran’s system of government?

The 1979 Iranian Revolution fundamentally transformed Iran from a monarchy under the Pahlavi dynasty into an Islamic republic, establishing a theocracy led by the Twelver Shi'ah clergy.123

The new system of government was built upon the theory of velāyat-e faqīh (governance of the jurist), which centralizes power in the office of the supreme leader (rahbar). While the state maintains democratic elements, such as a directly elected president and parliament (Majles), these institutions are constrained by clerical oversight. The Council of Guardians, for instance, vets candidates and legislation to ensure compliance with Islamic precepts.1234

Key changes included:
* Centralization of Power: The rahbar oversees government functions and commands the Islamic Revolutionary Guard Corps (IRGC), a powerful military branch accountable only to the leader.142
* Social Regulation: The regime enforced conservative social values, including strict codes of dress (hijāb) and public conduct (‘ifāf), and reversed previous legal protections for women.135
* Political Consolidation: Clerical factions systematically marginalized and excluded former left-wing, nationalist, and intellectual allies from power, entrenching a system where political parties are strictly regulated.236