How did the abolition of the prime minister's post in 1989 change the Iranian presidency?

In July 1989, a national referendum in Iran approved a constitutional amendment that abolished the post of prime minister, fundamentally transforming the Iranian presidency.1

Prior to this change, the presidency was largely a ceremonial position, with most government policy carried out by the supreme leader or the prime minister. Following the amendment, the president was vested with significantly greater authority, shifting from a symbolic role to one responsible for much of the day-to-day administration of the government.123

Key changes to the president's powers included:
* Executive Leadership: The president became the head of the executive branch, responsible for implementing laws enacted by the legislature.1
* Cabinet Oversight: The president gained the authority to select the Council of Ministers for legislative approval.1
* Security and Policy: The president serves as the chairman of the Supreme Council for National Security, which oversees national defense, and manages a wide range of government offices and organizations.1