Imam made denunciation this time in response to the "capitulations" or diplomatic immunity granted to American military personnel in Iran by the Shah.
In Nov. 1964 Imam Khomeini was re-arrested and sent into exile. Imam Khomeini spent over 14 years in exile, mostly in the holy city of Najaf in Iraq.
Logically, in the 1970s, as contrasted with the 1940s, he no longer accepted the idea of a limited monarchy under the Iranian Constitution of 1906-1907, an idea that was clearly evidenced by his book Kashf-e Asrar.
In his Islamic Government (Hokumat-e Islami) — which is a collection of his lectures in Najaf published in 1970 — he rejected both the Iranian Constitution as an alien import from Belgium and monarchy in general.
He maintained that the Shah regime was an un-Islamic and illegitimate institution usurping the legitimate authority of the supreme religious leader (Faqih), who should rule as both the spiritual and temporal guardian of the Muslim community (Umma).
In early 1970 Imam Khomeini gave a lecture series in Najaf on Islamic Government which later was published as a book titled variously Islamic Government or Guardianship of the Islamic Jurists (velayat-e faqih). This was his most famous and influential work and laid out his ideas on governance (at that time):
Only two weeks after the Shah fled Iran on January 16, 1979, Imam Khomeini returned to Iran triumphantly, on Thursday, February 1, 1979, invited by the anti-Shah revolution which was already in progress.
Conservative estimates put the welcoming crowd of Iranians at least three million. When Imam Khomeini was on plane on his way to Iran after many years in exile, a reporter, Peter Jennings asked him: "What do you feel?" and surprisingly Imam Khomeini answered "Nothing!"
In a speech given to a huge crowd on the first day of returning to Iran, Imam Khomeini attacked the government of Shapoor Bakhtiar promising "I shall punch their teeth in." He also made a variety of promises to Iranians for his coming Islamic regime: A popularly elected government that would represent the people of Iran.