Contemporaneous with the postrevolutionary power struggle, the new state faced a series of external threats. The obsessive fear of American intervention was confirmed by the botched April 1980 mission to rescue the hostages. And while Tehran initially maintained slightly better relations with Moscow, these too gradually eroded because of the Soviet occupation of Afghanistan and Iran's 1981–2 crackdown on the Tudeh Party. Closer to home, after an initial welcome elsewhere in the Muslim world, the new regime's honeymoon quickly ended; between the hostage crisis and Khomeini's provocative rhetoric, Iran's neighbors grew justifiably alarmed at Tehran's promise to “export the revolution.” The Islamic Republic found itself profoundly isolated as a result of its own statements and policies, and isolation only heightened its leadership's paranoia and hostility toward the international system.

In September 1980, after months of deteriorating relations and low-level violence in Khuzestan and along the Shatt al-Arab naval passage, Saddam Hussein invaded Iran and began what would become the longest and bloodiest war between two states since the Korean conflict. At home, the revolutionary state remained caught in the throes of turmoil on the streets and increasingly violent competition within the establishment, exacerbated by the July 1980 failed coup attempt.

The Iraqi invasion changed everything for Iran. It was an existential conflict that required a Herculean effort to sustain – an exigency complicated by the state's isolation and its leaders' conviction that the invasion represented only the first front in an international conspiracy to extinguish the revolutionary regime. From the outset, the conflict violently transformed the Iranian economy – denying the new government key ports, devastating thousands of square miles of territory, leaving millions internally displaced, altering export routes, destroying refining and petrochemical facilities, and heightening fears about the new state's survival.

Yet, despite the exigencies of the war effort, the political competition initiated during (and left unresolved by) the revolution raged on.