Khamenei's role as an active politico-religious leader of the Islamic Revolution continued in his appointment on January 14, 1980, by Ayatollah Khomeini as the Imam of Tehran's Friday congregational prayer. He used his religious platform to respond to the internal and external enemies of the Islamic Republic by sending them strong warnings. As a result of internal instabilities and escalation of internal crises, the necessity of forming an Islamic party intensified among Khomeini's top lieutenants. Khamenei considered the party crucial for protecting the entire political system, resolving internal crises, establishing the necessary branches of government, and advancing the regime. The weaknesses in Iran's military-security apparatus inherited from the Shah's regime necessitated the formation of a new military body based upon Khomeini's Islamic revolutionary principles. Khamenei explains that 'the American government, the president, and his national security adviser used to encourage the Shah to take decisive action during the last few months of the rule of his oppressive government'.