Power is impermanent in the Middle East. Strength tends to ebb and flow among the four major players in the region – Iran, Saudi Arabia, Turkey and Israel – and outside actors like the United States and Russia are always in the mix, playing the countries, and the various ethnic groups that constitute their populations, off of one another in pursuit of their own interests.

In the current state of play, Iran, with its Persian, Shiite sensibilities, is a power on the rise. For years, it has expanded its influence at the expense of its Arab rivals, which have been preoccupied by military conflict, civil unrest and low oil prices. Its rise has naturally aggravated tensions in the region that show no signs of abating. On May 21, U.S. President Donald Trump visited Saudi Arabia, during which he seemed to align Sunni Muslim nations against Iran. On May 19, Iran re-elected President Hassan Rouhani – a moderate by Tehran’s standards who helped broker the nuclear deal with the United States – to another four-year term.

It’s tempting, then, to assume these trends will continue. But a country’s behavior is dictated not by speeches and elections but by geopolitical imperatives and constraints – and Iran has several constraints that will limit the extent to which it can project its power.


Iran is more formidable on paper than perhaps it is in practice. It is the 17th-largest country in the world and the 17th-most populous. It is the sixth-largest producer of oil and the third-largest producer of natural gas. And, according to the International Monetary Fund, it boasts the world’s 29th-largest economy by gross domestic product despite decades of economic sanctions against it.

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But Iranian power is kept in check, sometimes by features beyond its control. The most important feature is geography. Modern Iran is almost completely enclosed by mountains. The Zagros Mountains, which run from the southern Caucasus to the Persian Gulf before breaking east along the gulf itself, form Iran’s western and southern flanks. The Alborz Mountains, which run east-west along the Caspian Sea in Iran’s northern frontier, separate Iran from Turkey, Azerbaijan, Armenia and Turkmenistan. To the east, mountains separate Iran from Afghanistan and Pakistan.

And though all these ranges form natural barriers that protect Iran from invasion, they also obstruct outward expansion. For Iran, defense comes easy; offense comes hard.

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Iran is also constrained by demography. The country has several large minority populations, including Azeris, Kurds, Arabs and Baluchis, all of which have separatist tendencies. Since its founding in 1979, when it toppled the secular monarchy, the current regime has tried to solve this problem by cultivating a national identity steeped in Shiism. (The shared use of the Persian language has also helped in that regard. In fact, historically, it has influenced the cultures and civilizations of peoples in all the surrounding regions.) But religion can go only so far. Its efforts have not exactly endeared the government to the Sunni minorities that populate Iran’s farther reaches. And the clerics who dominate the government are often at odds with the country’s republican institutions.

Iran Alone

Problematic though these ethnic and sectarian differences may be for domestic Iranian politics, they also affect the geopolitics of the region. The Caucasus, the Middle East and South Asia all have large Shiite populations, but Iran alone has a government that incorporates the religious practices of the majority of its citizens. And it is surrounded by Sunni majority states that are often hostile to its interests. (There are notable exceptions, of course. Azerbaijan is mostly Shiite but has a secular government; Bahrain is mostly Shiite but has a Sunni monarchy; and Iraq is mostly Shiite but has a mostly ineffectual government.)

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And so Iran doesn’t have too many options for projecting power. It can’t go east, even if it wanted to involve itself in the troubles of Afghanistan and Pakistan. It can’t go north, lest it encroach on territory traditionally under the influence of Russia. It can go only west, toward the Middle East.

But this strategy cuts both ways. The west may be the only avenue for expansion, but it is also one of the only avenues for invasion – which happened intermittently from the 3rd century to the 7th century, the 16th century and as recently as 37 years ago. Iran’s national security strategy, therefore, is to ensure that threats to its west are neutralized – no easy feat, considering most of Iran’s neighbors are majority Sunni Arab.

After the Iranian Revolution, with few friendly states to ally with, Iran had to get creative when war broke out with Iraq in 1980. Fortunately for Iran, there were no shortage of disenfranchised Shiite groups in the Arab world ready to rally to the banner of Shiite Islam, which the government in Tehran has championed since its founding. The timing of the revolution was fortuitous: Islamist groups were gaining popularity and secular ones were losing it. As Iran advocated pan-Islamism, it found an audience ready to accept it.

Tehran was thus able to link up with Shiite Arab forces. The first and most important instance was in Lebanon. From the Lebanese civil war, and the Israeli invasion that followed in 1982, rose Hezbollah, a group that had been nurtured by Iran and by another important Arab ally: Syria, the only state that would align with Iran.

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Syria did so for a few important reasons. First, the government in Damascus was headed by the Assad clan, which belongs to the sect of Shiite Islam known as the Alawites. The Assads and the Alawites headed the Syrian Baath Party, a bitter rival of the Iraqi Baath Party, led by Saddam Hussein, who was at war with Iran at the time of the alliance. The Iraqis were being supported by Saudi Arabia, which in 1981 formed the Gulf Cooperation Council with the other oil-rich Arab monarchies of the Persian Gulf.

The strategy was largely successful: Iran was able to use sectarian differences in the region, as well as disagreements among Arabs, to carve out space to operate in the Levant. On a much smaller scale, Iran also tried to support smaller Iraqi Shiite groups and Kurdish factions to counter the Iraqi government.

Still, the Islamic republic was preoccupied by war for much of the first decade after its founding – much to the delight of Saudi Arabia, arguably Iran’s main rival. The revolution brought to power a sect Riyadh considered heretical, and Riyadh was content to watch it take its hits. The Saudis, moreover, feared the prospects of similar successful uprisings against monarchies, especially since the new government in Iran openly sought to export its revolution. And the government in Iran offered a competing model of Islamic rule in a republic, something that ran counter to the notion of absolute monarchies.

A Rare Upper Hand

Saudi Arabia continued to benefit from the Iran-Iraq War even after it ended in 1988. Iran was too busy with reconstruction efforts at home to pose much of a threat, and the United States, a Saudi ally, levied sanctions against the government in Tehran.

But another conflict was slowly brewing between Kuwait and Iraq, a buffer state that protected the Arabian Peninsula from Iranian expansion. The conflict culminated in the Persian Gulf War, of course, leaving Iraq in a pretty weakened state.

The very country that protected the rest of the Arab world had become a liability – and had to be neutralized. Most Arab states, including Saudi Arabia, supported the U.S.-led war against Baghdad as well as the sanctions that followed for the next 12 years. During that time, Iran was largely left alone, free to rebuild itself. The Saudis didn’t like it, but there wasn’t much they could do about it, busy as they were trying to manage the emergence of al-Qaida.

Al-Qaida would go on to carry out the attacks on Sept. 11 against the United States, attacks that would have profound consequences for the Middle East. The United States would cooperate with Iran, albeit briefly, in the subsequent invasion of Iraq in 2003. Saudi Arabia opposed the move because it knew that if Saddam Hussein fell, he would be replaced with a Shiite state allied with Iran.

That’s exactly what happened. In just a few months, Iraq went from being a threat to Iran to an ally. In the years that followed, U.S.-Iranian relations were marked by a complex game of competition and cooperation for influence in Iraq. But by the time the U.S. left Iraq, another phenomenon had taken hold in the Middle East, one that would threaten the very foundation of Saudi power: a series of uprisings known (perhaps inaccurately) as the Arab Spring. The Persians now had the upper hand in the Levant and in Mesopotamia, a situation they had not been in for a long time. (The last time the Shiites enjoyed this kind of geopolitical power was when the Safavid Empire battled the Ottomans in the 1550s, when they didn’t even control Iraq, much less Syria.)

And yet Iran faced limitations. Tehran’s foray into the Arabian Peninsula – some modest support for the Shiite uprising in Bahrain, which lay right across from Saudi oil fields – was quickly suppressed by Saudi security forces. But the bigger upset for Iran came in Syria, where civil unrest turned into civil war. Saudi Arabia, Turkey, the United Arab Emirates and Qatar have all supported rebel forces. For the first few years, it seemed as though the Assad government might fall. With help from Russia and Iran, the government has regained a lot of the territory it had once lost, even though it is still a shadow of its former self.

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Iran’s other allies are in no better shape. Though it has made considerable gains against the Islamic State and has retaken most of Mosul, the Iraqi government is unstable and unreliable. Elsewhere, in Yemen, where the Saudis are engaged in their first major war beyond their borders, the pro-Iranian Houthi movement remains contained. In Lebanon, Hezbollah is spread thin by its commitment to the war in Syria.

Too Many Constraints

Iran appears to have exploited its opportunities in the Arab world as much as it can, at least for now. There are simply too many constraints on Iranian power. Unable to deploy conventional military forces, it must rely on proxy groups and Shiite militias to do its bidding. It cannot afford to upset the United States, which seeks a balance of power in the Middle East and will therefore not allow Iran to gain too much power at the expense of the Arabs. The government in Tehran must make sure that the sanctions relief it got from the nuclear deal remains intact.

The Iranians hope to benefit from the war against the Islamic State, but it is not a war in which they have much room to maneuver. The best they can hope for is a continued disconnect between the Americans and the Turks. Turkey cannot afford to remain on the sidelines of Syria for too long, and Ankara’s own imperatives will force it to get involved in the Levant, where Iran will face serious challenges.

The Arabs don’t want the Turks to dominate the region. But here again they have little choice. As Saudi Arabia weakens, it must deal with Iranian power, even as it deals with the Islamic State, al-Qaida and other jihadist groups. Squeezed between the Shiites and the jihadists, the Arabs will have no choice but to rally around the Turks, who are at least fellow Sunnis.

Iran will continue to hold on to the power it has accrued, and through its proxies it will continue to influence the region. But it cannot dominate a region that is majority Arab and majority Sunni.