Prime ministership of Mir-Hossein Mousavi secret negotiations and dealing with USA on helping them free the American hostages in Lebanon, in return for sale of the American weapons and spare-parts that Iran's army badly needed for Iran–Iraq War. Shortly after the end of Iran–Iraq War on 20 August 1988, Ruhollah Khomeini died, and Ali Khamenei was elected as the new Supreme Leader by the Assembly of Experts. Following his death, Mousavi and his fellow left-wingers lost their main source of support within the establishment. During the parliament hearing on post-war reconstruction plans, Mousavi had heated arguments with Ali Akbar Hashemi Rafsanjani, the speaker of Iran's
Mir-Hossein Mousavi as well as the conservative newspaper "Jomhouri-e Eslami", supported Mousavi's candidacy, he did not receive the official backing of any major conservative party. His candidacy made it harder for the conservatives to support Mahmoud Ahmadinejad, and large conservative parties, such as the Combatant Clergy Association, did not back the current President for a second term of office. Mousavi had on numerous occasions indicated his wish to change the constitution in order to remove the existing ban on the private ownership of television stations (currently all Iranian television stations are state-owned), as well as transfer the control of the law-enforcement forces