MORE THAN thirty years after Ayatollah Ruhollah Khomeini came to power—and two decades after his passing—the Islamic Republic remains an outlier in international relations. Other non-Western, revolutionary regimes eventually eschewed a rigidly ideological foreign policy and accepted the fundamental legitimacy of the international system. But Iran’s leaders have remained committed to Khomeini’s worldview. The resilience of Iran’s Islamist ideology in the country’s foreign policy is striking. China’s present-day foreign policy isn’t structured according to Mao’s thought, nor is Ho Chi Minh the guiding light behind Vietnam’s efforts to integrate into the Asian community. But Iran’s leadership clings to policies derived largely from Khomeini’s ideological vision even when such policies are detrimental to the country’s other stated national interests and even when a sizable portion of the ruling elite rejects them.

Many Western observers of Iran don’t understand that its foreign policy has been fashioned largely to sustain an ideological identity. Thus, we can’t understand Iran’s foreign relations and its evident hostility by just assessing its international environment or the changing Mideast power balance. These things matter. But Iran’s revolutionary elite also seeks to buttress the regime’s ideological identity by embracing a confrontational posture.

The question then becomes why the Iranian leadership continues to maintain this ideological template so long after its revolutionary emergence. After all, other revolutionary regimes, after initially using foreign policy for ideological purposes, later moved away from that approach. Why has China become more pragmatic but not Iran? The answer is that the Islamic Republic is different from its revolutionary counterparts in that the ideology of its state is its religion. It may be a politicized and radicalized variation of Shia Islam, but religion is the official dogma. Thus, a dedicated core of supporters inevitably remained loyal to this religious ideology long after Khomeini himself disappeared from the scene. Revolutionary regimes usually change when their ardent supporters grow disillusioned and abandon the faith. It is, after all, much easier to be an ex-Marxist than an ex-Shiite. In one instance, renouncing one’s faith is political defection; in the other, apostasy. Although the Islamic Republic has become widely unpopular, for a small but fervent segment of the population it is still an important experiment in realizing God’s will on earth.

To understand this, it helps to review some pertinent Iranian history, beginning with the thought and actions of Ayatollah Khomeini. Khomeini offered a unique challenge to the concept of the nation-state and the prevailing norms of the international system. The essence of his message was that the vitality of his Islamist vision at home was contingent on its relentless export. Moreover, because God’s vision was not to be confined to a single nation, Iran’s foreign policy would be an extension of its domestic revolutionary turmoil. For the grand ayatollah, the global order was divided between two competing entities—states whose priorities were defined by Western conventions; and Iran, whose ostensible purpose was to redeem a divine mandate. Of course, no country can persist on ideology alone. Iran had to operate its economy, deal with regional exigencies and meet the demands of its growing population. But its international relations would be characterized by revolutionary impulses continually struggling against the pull of pragmatism.

Khomeini’s internationalism had to have an antagonist, a foil against which to define itself. And a caricatured concept of the West became the central pillar of his Islamist imagination. The Western powers were rapacious imperialists determined to exploit Iran’s wealth for their own aggrandizement. Islamist themes soon followed, portraying the West as also seeking to subjugate Muslims and impose its cultural template in the name of modernity. Disunity among Muslims, the autocracies populating the region, the failure of the clerical class to assume the mantle of opposition and the young people’s attraction to alien ideologies were seen as byproducts of a Western plot to sustain its dominance over Islam’s realm. Four episodes from the 1980s underscore how foreign policy was used to buttress the ideological transformation at home: the 1979–1981 hostage crisis, the war with Iraq, the events surrounding the Salman Rushdie fatwa and a Khomeini-ordered massacre of political prisoners.

It is often forgotten that those in charge during the initial stages of the 1979 revolution were not Khomeini’s clerical militants. During a power struggle between the clerics and the provisional government’s moderates, the provisional government did not seek to break ties with the United States. Although Tehran would not be a pawn in the U.S.-Soviet conflict, it wished to maintain normal diplomatic and economic relations with Washington.

Thus, Khomeini and his clerical allies increasingly saw the provisional government as an impediment to their larger objectives. The task of redrafting the constitution along radical lines and electing a clerically dominated parliament required displacing the provisional government. In the end, this combination of concerns pressed the radicals to provoke a crisis that would galvanize the populace behind the cause of the Islamic Republic and its ideological mandates.

On November 4, 1979, a group of Iranian students breached the walls of the U.S. embassy and captured sixty-six Americans. They remained hostage for 444 days. The embassy takeover provided Khomeini with his opportunity to inflame popular sentiment and claim that external enemies, aided by domestic accomplices, were plotting against the revolution. To a frenzied populace, it seemed plausible that the United States, which had used its embassy to restore the Pahlavi dynasty to power in 1953, was now up to similar mischief. The Iranian public rushed to the defense of the revolution, and Mehdi Bazargan’s provisional-government premiership soon faded.

On December 2, 1979, a draft constitution favored by Khomeini, which granted essential power to the unelected branches of government, was submitted to the public. Khomeini warned that its rejection at such a critical juncture would demonstrate signs of disunity and provoke an attack by the United States. The regime’s propaganda machine insisted that only secular intellectuals tied to U.S. imperialism were averse to the governing document. It worked: fully 99 percent of the population voted for the constitution.

Out of this emerged two other factors—namely, the clerics’ quest to usher in a militant foreign policy and their desire to strike a psychological blow against the United States. The provisional government’s approach to international relations was strict nonalignment with a willingness to pursue normal relations with the United States. This formulation was rejected by the newly empowered militants, who provoked the hostage crisis to foster a different international orientation. Under this orientation, Iran’s foreign policy would become not merely an exemption from the superpower conflict but an assertion of radical Islamism as a foreign-policy foundation. Through a symbolic attack on the U.S. embassy, the new revolutionaries not only consolidated their domestic power through their antagonism toward the United States but also demonstrated their contempt for prevailing international norms. Iran now would inveigh against the United States, assist belligerent actors throughout the Middle East and plot against the state of Israel.

IRAN’S WAR with Iraq was the next big event in this saga of the Iranian elite’s resolve to meld domestic and foreign policy. The triumph of Iran’s revolution, with its denial of the legitimacy of the prevailing order and its calls for the reformulation of the state structure along religious precepts, portended conflict. Revolutions are frequently followed by war, as newly empowered elites often look abroad for the redemption of their cause. In Iran, the new elite mixed aggressive propaganda, subversion and terrorism to advance its cause in Iraq, where minority Sunnis dominated the majority Shia population. Perhaps nowhere was Iran’s message of Shia empowerment received with greater acclaim than among Iraqi Shiites. This provocative behavior contributed to Saddam Hussein’s decision to invade Iran in 1980, which ignited one of the region’s most devastating conflicts.

The Iranian clerical state didn’t measure progress in the Iran-Iraq war in territory lost or gained, boundary demarcations or reparation offers. Rather, it saw the war as an opportunity to merge its religious pedigree with its nationalist claims. The war was viewed as a struggle against an assault on Islam and the Prophet’s legacy by profane forces of disbelief. The clerical estate genuinely identified itself with the Prophet’s mission and saw Saddam’s secular reign as yet another manifestation of inauthenticity and corruption. Iran had not been attacked because of its provocations or lingering territorial disputes but because it embodied Islam and sought to achieve the Prophet’s injunctions. Thus, it was the moral obligation of the citizenry to defend Iran as if it were safeguarding religion itself.

By June 1982, Iran essentially had evicted Iraq from its territory, and the question emerged whether to continue the war by going into Iraq. Given the war’s economic costs and human toll, the decision to attack Iraq remains one of the most contentious in Iran’s modern history. Khomeini resolutely dismissed various offers of cease-fire and generous reparations. Instead, Iran embraced a disastrous extension of the conflict based on a combination of ideological conviction, the misperception that the war would be quick and a fear that Saddam would not remain contained.

The rationales underlying Iran’s decision to prolong the war still are debated widely. The conventional view discounts the notion that prolonging the war was seen as a means of consolidating the revolution at home. But Khomeini soon celebrated the decision as the “third revolution,” whose purpose was not just to repel the invaders but also to cleanse Iran of all secular tendencies. In order to exploit the war politically, the state had to present the conflict in distinctly religious terms. A revolutionary order seeking to usher in a new era could not wage a limited war designed to achieve carefully calibrated objectives. The war had to be a crusade—indeed, a rebellion against the forces of iniquity and impiety. Through collective sacrifice and spiritual attainment, the theocratic regime would fend off the invaders, change Iran and project power throughout the region.