Since the 1979 Iranian revolution replaced a U.S.-allied monarchy with a bitterly anti-American theocracy, Washington’s foreign policy in the oil-rich Persian Gulf has rested on two strategic pillars: enmity with Iran and amity with Saudi Arabia. In recent months, however, this thirty-five-year status quo has been called into question by a rapidly changing Arab political order and the promise of a U.S.-Iran nuclear détente.

The combination of the interim nuclear deal with Iran, U.S.-Saudi regional disagreements, and America’s newfound shale wealth has prompted predictions of a fundamental realignment of the geopolitical chessboard, with Tehran supplanting Riyadh as Washington’s chief regional ally. Rather than swap one ally for another, however, U.S. President Barack Obama has articulated a revised approach to the Middle East. The United States will no longer seek to isolate Iran but will instead attempt to “get Iran to operate in a responsible fashion” to foster a “new equilibrium” between Iran and Saudi Arabia that will be marked by “competition, perhaps suspicion, but not an active or proxy warfare.”

No bilateral relationship in the Middle East is more consequential for the region’s future and U.S. interests than that between the Kingdom of Saudi Arabia and the Islamic Republic of Iran. On nearly every single major issue in the Middle East, Tehran and Riyadh appear to be on opposing sides, confounding America’s efforts to bring stability. The two countries are at once ethnic (Arab vs. Persian), sectarian (Sunni vs. Shia), and geopolitical rivals, vying for power and influence throughout the Persian Gulf, the Levant, the Palestinian territories, and Iraq as well as within the Organization of the Petroleum Exporting Countries (OPEC). In addition, they each embrace radically different forms of government and advance divergent visions for Middle Eastern order, disagreeing most sharply over the question of America’s presence in the region.

Frederic Wehrey Frederic Wehrey is a senior fellow in the Middle East Program at the Carnegie Endowment for International Peace. His research deals with armed conflict, security sectors, and identity politics, with a focus on Libya, North Africa, and the Gulf. More >

In light of these differences, the two states are likely to remain perpetual competitors. The question now is whether their competition must manifest itself in protracted proxy conflict or whether—like France and Germany in Europe—the two states can settle on a peaceful modus vivendi that, while falling short of genuine friendship, could help de-escalate sectarian tensions across the region.

The stakes for the United States in terms of both its projected disengagement from the Gulf and Obama’s notion of a regional “equilibrium” are enormous. Washington’s bilateral relations with Riyadh and Tehran may help facilitate some movement toward a repair of relations. But U.S. policymakers should harbor no illusions about the difficulty of this task, given the deep history of distrust between the Saudi Arabia and Iran, the fractured regional landscape that exacerbates their rivalry, and the disparate outlooks of their respective ruling elites.

The Roots of Enmity

Saudi Arabia and Iran are each endowed with unique assets. In the overwhelmingly Sunni Arab Middle East, Saudi Arabia’s custodianship of Islam’s holiest sites, coupled with its vast energy reserves, offer it clear advantages. Iran’s long history as a nation-state, demographic superiority, and ability to project power abroad offer it competing advantages. Each country also considers itself the natural leader of the broader Muslim world, Saudi Arabia because of its religious credentials and Iran because of its ideological bona fides as a bulwark against Israel and America.

These differences and designs have driven hostility over the years. Yet, the two sides have in the past shown an ability to compartmentalize their rivalry, reaching a tenuous truce in one geographic sphere while simultaneously engaging in heated confrontation in another.

The closest parallel to a Gulf-based equilibrium was the uneasy Saudi-Iranian partnership that existed under the shah of Iran in the late 1960s and 1970s. In the prerevolutionary era, Iran and Saudi Arabia were linked by monarchical solidarity in the face of communist and republican threats and by their mutual patronage from the United States. The regional order at that time was less unsettled, inviting fewer opportunities for competition between the two sides.

But a return to that era is highly unlikely given the state of upheaval and conflict in the region today and the two states’ drastically different domestic politics. Indeed, antagonism and mistrust between the two—and between each of these countries and the United States—has peaked in recent months.

Saudi officials have reacted cynically and suspiciously to the seemingly more moderate demeanor Iran has adopted of late. Its new president, the pragmatic cleric Hassan Rouhani—a protégé of former Iranian president Akbar Hashemi Rafsanjani—is poised to improve relations with Riyadh, reaching out to rebuild ties that deteriorated during the era of bombastic former president Mahmoud Ahmadinejad. What remains in question is to what extent Rouhani and his foreign minister, Mohammad Javad Zarif, are empowered to meaningfully alter regional policies, which have long been the domain of Supreme Leader Ali Khamenei and the Islamic Revolutionary Guard Corps, a formidable military force under his command.

Karim Sadjadpour Karim Sadjadpour is a senior fellow at the Carnegie Endowment for International Peace, where he focuses on Iran and U.S. foreign policy toward the Middle East. @ksadjadpour

What’s more, the interim nuclear deal struck in November 2013 between the five permanent members of the UN Security Council plus Germany (known as the P5+1) and Tehran effectively formalized a catastrophe the Saudis long feared: a bait and switch that bought Tehran time on the nuclear front while empowering Iran to pursue its own interests across the region, particularly in Syria, where it supports the regime of its ally Bashar al-Assad in the ongoing civil war.

In response, senior Saudi officials have been uncharacteristically public about advocating a more muscular and independent Saudi policy to step up the battle against Iran. They have lambasted Tehran’s “destabilizing” role in the Middle East, openly chastised America for being too ready to concede to Iran’s nuclear and regional ambitions, and warned that Riyadh may confront Tehran on its own. For their part, Iranian officials excoriate Saudi Arabia’s support for radical Sunni jihadists and its alliance with the United States, and they predict that Riyadh’s geriatric leadership is on the verge of collapse.

Beneath this mutual venom, an array of conflicts in fractured states is inviting meddling by the two powers, fueling a zero-sum struggle for influence that is unlikely to abate in the near term.

Syria: Center of the Storm

As the political crisis in Syria has deteriorated into a humanitarian crisis of epic proportions—as of this writing, there have been over 150,000 casualties and 9 million people either internally or externally displaced—a war-weary U.S. president, Congress, and populace have been reluctant to intervene given uncertainty about Washington’s interests. Growing concerns about radical elements of Syria’s rebel forces, coupled with the Assad regime’s brutal resilience, have seemingly downgraded U.S. priorities from the removal of the Syrian dictator to merely the removal of his chemical weapons.

For Iran and Saudi Arabia, in contrast, Syria has become the epicenter of a geopolitical-cum-sectarian bloodbath.

Iran has been strategically isolated since the 1979 revolution, and Syria has been its only consistent ally. A mutual antipathy toward Saddam Hussein’s Iraq spawned the partnership between Tehran and Damascus, and shared fear and loathing of America and Israel has sustained it. Syria provides Tehran a critical geographic thoroughfare to arm and finance the Lebanese Shia militia Hezbollah, one of the crown jewels of Iran’s revolution.

Tehran thus is strongly motivated to keep the Assad regime in power. Its stance is driven less by sectarian solidarity than by deep concerns about what might come after Assad. Syria’s population is overwhelmingly Sunni Arab, although the country is currently ruled by Alawites, a Shia sect. If Assad falls, Tehran fears that a Sunni sectarian regime aligned with Saudi Arabia and hostile to Shia Iran could come to power in Damascus.

Iran is primarily concerned not with the sectarian composition of Syria’s leadership but with whether these leaders share Tehran’s ideological worldview and its premise of resistance against America and Israel. As Khamenei once said, “We will support and help any nations, any groups fighting against the Zionist regime across the world.” And Iran has given just that support to the Assad regime. Tehran has provided Assad billions of dollars in loans, credits, and subsidized oil in order to keep the Syrian regime solvent, and it has offered conventional and unconventional military aid as well as intelligence training and cooperation to help crush popular unrest.

According to both U.S. government reports and Iranian official statements, Tehran has also helped create a 50,000-strong Syrian paramilitary group known as Jaysh al-Shabi (the People’s Army) to aid Syrian government forces.

By contrast, Saudi Arabia is outraged by the large-scale and indiscriminate slaughter of Sunni Arabs at the hands of a Shia-supported, Alawite dictatorship. Riyadh regards the Levant as ground zero in its geostrategic struggle with Iran, a make-or-break opportunity to clip Tehran’s wings in the Arab world and alter the regional balance of power back in Saudi Arabia’s favor.

The anti-Assad uprising has provided Saudi Arabia and the Gulf with a new chance to weaken Iran. Saudi and Gulf support to the Syrian opposition escalated in early 2012 with the intervention of Hezbollah and Revolutionary Guards forces. At the same time, Riyadh appears to be fighting simultaneous wars against al-Qaeda elements within the Syrian opposition and, to a lesser extent, the Muslim Brotherhood. A key unknown is whether the cost of this three-front struggle will eventually exhaust the Saudis, forcing them into quiet talks with Iran to prevent an outcome that both sides fear: the rise of transnational al-Qaeda affiliates with a reach beyond Syria’s borders.

The Obama administration’s denouncement of Assad, coupled with its reluctance to decisively remove him from power, has led to charges that Washington is either collaborating with both Tehran and Riyadh or cynically allowing the conflict to fester as a means of hemorrhaging Iran, Hezbollah, and al-Qaeda.

In reality, the risks of continued carnage in Syria are grave for Washington, Tehran, and Riyadh. Iran’s support for Assad has had not only an enormous financial cost but also a perhaps irreparable reputational cost in the predominantly Sunni Arab Middle East. Riyadh’s backing of rebel groups could boomerang against the kingdom when and if jihadist factions in Syria either prevail or are decisively defeated. And the United States must worry about the prospects of an al-Qaeda-infested failed state that destabilizes neighboring countries such as Lebanon and Jordan.

Despite these risks, however, both Tehran and Riyadh appear convinced of the righteousness of their positions, and neither has shown concrete signs of recalibrating. In this context, America’s interest in seeing both an end to the Assad regime and the weakening of radical Sunni Islamists will create tactical convergence and strategic clashes with Tehran and tactical clashes and strategic convergence with Riyadh. But as long as Syria remains an Alawite-led minority brutally ruling over a Sunni-majority population, Iran–Saudi Arabia tension and its resulting regional disequilibrium will likely persist.

Iraq: The Contested Frontier

Iraq is the lone country that borders both Iran and Saudi Arabia. More than eleven years after the U.S. invasion of Iraq, the country remains embattled internally and continues to be a significant source of regional tension and resentment against Washington.

Viewed from Riyadh, if America’s sin of omission in Syria has been to Iran’s benefit, America’s sin of commission in Iraq—the 2003 removal of then Iraqi president Saddam Hussein—was an enormous gift to Tehran. In just over a decade, formerly Sunni-led Iraq has been rendered a Shia-dominated state on the eastern frontiers of the Arab world and is now led by a man, Prime Minister Nouri al-Maliki, whom Saudi King Abdullah reportedly considers an Iranian agent.

Rather than aggressively contend with Iranian power as it does in the Levant, Saudi Arabia has pursued a passive policy of static containment or damage control in Iraq. Given the country’s Shia majority, Saudi officials concede that they are playing a losing game in trying to stem Tehran’s influence, bereft of the local networks, access, and capacity that Iran enjoys. “You have to hand it to them,” a Saudi official told one of the authors in 2007. “The Iranians had a plan before the 2003 invasion and acted on it. They deserve the influence they got.”

Saudi officials seemingly see little benefit in expending energy on countering Iranian influence in Iraq when the more pressing—and decisive—struggle is in Syria. Yet worsening sectarian tension throughout the Middle East as a result of the Syrian conflict has pushed the Maliki government closer to Tehran and further from its Arab brethren.

For Iranians, a deep lingering resentment over U.S. and Saudi support for Saddam Hussein during the Iran-Iraq war—in which Iran suffered several hundred thousand casualties, including as a result of Saddam’s use of chemical weapons—remains a powerful motivation for ensuring a Tehran-friendly government in Baghdad.

Iraq’s importance as an ally to Iran has only grown given the uncertain future of the Assad regime. Tehran has used Iraq as a critical thoroughfare to smuggle its oil, subvert financial sanctions, and arm and finance the Assad regime. This arrangement, in turn, has deepened Riyadh’s contempt for the Maliki government, which Saudi Arabia considers complicit in Assad’s large-scale massacres and, increasingly, the plight of Iraq’s Sunnis in the troubled Anbar Province, who are embroiled in violent conflicts with the Iraqi Army.

As elsewhere in the region, it is often difficult discern to whether Iran considers itself embattled by both U.S. and Saudi influence in Iraq or whether Tehran distinguishes between the two. Whereas during the Ahmadinejad era Iranian officials tended to see the United States and Saudi Arabia as a unitary evil, more recently Tehran has made efforts to distinguish between its hegemonic (America) and sectarian (Saudi) foes.

As the U.S. presence in Iraq withers, Iran will have more opportunities in the country, but it will also face greater obstacles. Even among its co-religionists, Tehran has found there are limits to its influence. If the increasingly authoritarian practices of the Maliki government continue, it is Tehran, not Washington, that may soon be regarded by many Iraqis—both Shia and Sunni—as the meddlesome external power partly responsible for regime repression, growing insecurity across the country, and economic corruption.

It is likely that Saudi Arabia and the Gulf states will continue to be reticent and ambivalent about improving their relations with Iraq, even if Iraqi popular sentiment turns against Iran. In this sense, Washington’s long-standing hopes of convincing the Gulf Arab states to productively engage with Iraq to counterbalance Iran are ultimately misplaced. Iraq is likely to remain a contested frontier region for the two sides that is unlikely to devolve into open proxy conflict but is also unhelpful for a broader détente.

The Battle for Bahrain

In Bahrain as in Syria, a demographic minority rules over a majority, although it does so far less brutally. While the Sunni ruling al-Khalifa family is closely aligned with Riyadh, Iran has attempted—with mixed success—to portray itself as the champion of the disenfranchised Shia majority, thought to comprise around 70 percent of the population.

Iran has offered strong moral and limited material support to Bahrain’s Shia, some of whom regard Ayatollah Khamenei as their spiritual guide, or marja. But Tehran’s involvement in Bahrain is nowhere near the massive lethal, material, and financial support that Iran’s Qods Force—the overseas special operations unit of the Revolutionary Guards led by fabled commander Qassem Soleimani—has lent to Iraq’s Shia militants and is now providing to Alawite and government forces in Syria.

Tehran also views Bahrain as an outpost of U.S. imperialism in the Middle East because the island nation hosts the headquarters of the U.S. Navy’s Fifth Fleet, a hub of maritime command-and-control and logistics capabilities that Tehran interprets as a means for Washington to constrain Iran’s influence in the Gulf. Tehran hopes that greater Shia political influence in Bahrain could help Iran shut down a vital enemy garrison in its neighborhood. Up until now, however, much of Bahrain’s opposition has favored a continued U.S. presence in the country in order to balance against both Saudi and Iranian influence.

Saudi Arabia has inflated the Iranian menace into something it is not. In this sense, Riyadh has become trapped by its own narrative, which elevates what is essentially a local struggle over the distribution of economic and political power to the status of geostrategic competition with its Persian rival, accusing Iran of trying to foment another Khomeinist revolution.

In many respects, the Iranian menace has been used by Riyadh and the al-Khalifa to deflect attention from a homegrown movement for greater dignity and civil liberties. Some Saudi officials have recognized this reality, albeit privately. In 2006, for instance, a senior Saudi diplomat in Bahrain acknowledged that the Bahraini Shia were not pawns of an Iranian chess master. “We could live with an elected Shia prime minister in Bahrain,” he noted.

Saudi officials want Iran to declare that unrest in Bahrain is an internal Bahraini matter. Iran will continue to advocate for more representative government in Bahrain, which implicitly means greater Shia power and a diminution of Saudi influence.

But there are some signs that both Iran and Hezbollah, which has also supported Bahrain’s opposition, may be tempering their statements on Bahrain as part of Rouhani’s broader charm offensive. Whether this shift paves the way for more substantive de-escalation remains to be seen.

The United States has enormous stakes in Bahrain given the presence of the Fifth Fleet. A lowering of Saudi-Iranian tensions might enable more progressive factions within the ruling family to undertake more substantive reforms to quiet an increasingly radicalized opposition. This would not only improve the long-term viability of the monarchy but also stave off a potential threat to U.S. citizens and assets on the island. In addition, it would be a positive step toward establishing an equilibrium in the Gulf that could facilitate a diminishing need for U.S. military presence.

Israel-Palestine: Two States or One?

Both Iran and Saudi Arabia consider themselves patrons and guarantors of Palestinian nationhood and attach enormous domestic and regional legitimacy to these claims. But the Palestinian-Israeli conflict is another example of Tehran and Riyadh backing rival local factions with competing solutions.

Saudi Arabia supports a two-state solution and has recently backed U.S. efforts to revive a peace plan that King Abdullah first proposed in 2002. The plan offers Israel full recognition in exchange for a withdrawal to pre-1967 borders and the return of Palestinian refugees. Riyadh has also been the Arab world’s principal financial patron of the Palestinian Authority.

In contrast, since 1979 Iran has come to see the rejection of Israel’s existence as a critical source of its revolutionary identity and a means to transcend the Arab-Persian and Sunni-Shia divides in its bid for regional leadership. In pushing for a one-state solution, Iran has backed militant rejectionists such as Hamas and the Palestinian Islamic Jihad.

Moreover, and perhaps more importantly, Hezbollah, Iran’s principal proxy in the Levant, cites continued confrontation with Israel as its raison d’être for bearing arms. An Israeli-Palestinian settlement would seriously undermine this rationale.

Riyadh has vehemently opposed Iran’s support to militant Palestinian factions. In 2010, King Abdullah reportedly told then Iranian foreign minister Manoucher Mottaki that “you as Persians have no business meddling in Arab matters” after the Iranian diplomat had tried to justify Iran’s support to Hamas on the basis of Islamic solidarity. Saudi Arabia tried but failed to wrest Hamas away from Tehran by brokering a peace agreement between Hamas and rival Palestinian faction Fatah in 2007. The accord quickly fell apart amid street fighting. And despite Iranian differences with Hamas over Syria in 2011, Tehran appears to be restoring relations with the militant party—a further blow to Saudi influence in the Palestinian arena.

The growing convergence of Israeli and Saudi policies toward Iran’s nuclear program, fueled by a mutual perception in Riyadh and Tel Aviv of a U.S. retreat from the region, has further damaged Saudi Arabia’s standing among Palestinians.

That said, the Israeli-Palestinian conflict may not be a source of enduring, unsolvable enmity between Riyadh and Tehran. The Palestine issue is less of a zero-sum game in which the two sides are backing armed combatants on opposing sides of the sectarian spectrum than the conflict in Syria, for instance.

The Israeli-Palestinian conflict could, however, prove the single biggest impediment to the U.S.-Iran rapprochement that Saudi Arabia so desperately fears. For both Tehran and Washington, the question of Israel’s existence is a deeply entrenched issue of domestic politics; Israel has no greater ally than Washington and no greater adversary than Tehran. Even in the event of a nuclear deal between the United States and Iran, continued Iranian support for militant groups opposed to Israel’s existence would prevent a full normalization of relations between Washington and Tehran.

Oil: Necessity Trumps Ideology

The Washington-Riyadh alliance is premised on the United States providing Saudi Arabia security in order to ensure the steady flow of Saudi oil to the world. But that foundation is being shaken by America’s burgeoning indigenous shale energy industry, plans for a U.S. foreign policy rebalance to Asia, and a series of fierce disagreements over regional issues like Egypt, Syria, and Iran. Notwithstanding these differences, the United States has had no more reliable ally in OPEC than Saudi Arabia, which has traditionally been at loggerheads with Iran over oil-pricing quotas.

Whereas Tehran has in the past been more concerned about maximizing short-term profits, Riyadh has taken a longer view—a difference in temporal outlook that stems from each country’s oil reserves and production capacity. Iran has the world’s fourth-largest proven reserves (around 136 billion barrels), nearly half of Saudi Arabia’s 267 billion barrels of reserves. Due to a variety of factors—including sanctions and antiquated infrastructure—production costs in Iran are significantly higher than in Saudi Arabia: some estimates put the cost of extracting a barrel of oil in Iran at more than three times the cost of extracting a barrel in Saudi Arabia. Riyadh has in the past used its swing production capacity as a weapon against Iran—not just under the current round of sanctions but also before the revolution.

A number of new trends are challenging Saudi Arabia’s longtime primacy. Riyadh faces a shortage of global demand, growing internal demand, the re-entry of Libyan crude into the global market, and increased production from Iran with the easing of sanctions. If and when Iraq reaches its full production potential, Saudi standing could slip further. U.S. shale production, which is expected to peak in 2018, may force significant cuts in OPEC production over the next several years.

That said, these trends should not be overstated. Saudi Arabia retains enormous power as a swing producer, and its oil exports are critical to the economic health of global heavyweights like China, upon which the economies of the United States and Europe depend. Such linkages mean that Washington will continue to remain engaged in the protection of Saudi supplies regardless of American shale output.

For its part, mismanagement and sanctions have prevented Iran from fully exploiting its vast energy reserves. Tehran earned over $600 billion in oil revenue during Ahmadinejad’s tenure as president—around 60 percent of its total oil revenue over the last century. But that money was largely squandered on populist economic policies that exacerbated rather than ameliorated the country’s high inflation and unemployment. Since then, escalating economic and financial sanctions, notably a total European embargo on Iranian oil, have dropped Iranian production and exports by more than 50 percent.

Revamping Iran’s oil industry, production, and exports has been one of the key policy pursuits of the Rouhani government. Former oil minister Bijan Zanganeh—who served in the administration of reformist president Mohammad Khatami—was brought back to the helm, and he has courted Western (including American) oil companies and vowed to increase Iran’s production back to the status quo ante.

Of all the points of contention between Washington, Tehran, and Riyadh, oil-production differences may prove the most manageable. The respective oil ministers of each country, Zanganeh in Iran and Ali al-Naimi in Saudi Arabia, are technocrats, not ideologues. Yet much will hinge on a nuclear deal. If one is not reached, the United States will continue to inhibit, via sanctions, Iran’s production and export of oil.

Gulf Security and the U.S. Presence: The Elephant in the Room

At the heart of the Saudi-Iranian rivalry lies a simple irony: Iran mistrusts and fears the United States and wants it to exit the Gulf, yet Gulf Arab nations desire America’s continued security presence in the region precisely because these states fear and mistrust Iranian ambitions.

Since Shah Mohammed Reza Pahlavi instituted a military modernization program in the 1970s, Saudi Arabia has looked to an outside patron—Washington—to balance Iran’s superior strength. When Tehran calls for a regional, local solution to Persian Gulf security (that is, the departure of U.S. forces) Saudi Arabia immediately sees a design for Persian hegemony that harks back to the era of the shah, when Riyadh was consigned to the status of Washington’s junior partner.

Yet Saudi opposition to an indigenous, regional Gulf security architecture may eventually erode in the face of current and impending realities, such as the growing chasm with the United States and the fractured consensus among the Gulf states. Despite its vocal protestations and threats of a divorce with Washington, Riyadh has few if any other reliable options for an outside security guarantor. Russia, France, China, and India all have shortcomings and limitations related to their capacity and desire to project power in the Gulf—or sharp political differences with Riyadh on key issues like Syria and Iran.

Riyadh has called for greater steadfastness and cohesion among the Gulf Cooperation Council (GCC) states, the organization of Gulf Arab monarchies that was founded in part because of mutual concerns about Iran. But these calls have gone largely unheeded. While GCC countries continue to harbor private concerns about Iran, they have responded favorably to Iran’s charm offensive. Oman went so far as to publicly reject Saudi calls for greater defense cooperation among GCC states.

The Elusive Equilibrium

During times of relative regional tranquility, Tehran and Riyadh have shown an ability to manage their ethnic, sectarian, and ideological rivalries. But during times of regional turbulence, Saudi Arabia–Iran tension is self-perpetuating: the contentious regional environment deepens mutual ill-will, which in turn makes regional conflicts—such as the one in Syria—even bloodier.

While Washington’s long-standing impulse to align with Saudi Arabia against Iran in these conflicts has been severely strained, any U.S. strategy intent on improving ties with Tehran, and bringing about equilibrium between Tehran and Riyadh, will be equally challenging.

For one, despite the potential for a nuclear détente between the United States and Iran, there are few signs that Tehran’s senior leadership, particularly Khamenei, is genuinely interested in a constructive relationship with Washington. Even Iranian officials perceived as more moderate, such as Abbas Araghi, a senior nuclear negotiator, have consistently stressed that “enmity between . . . [Iran] and America is still in place. . . . America from our view is still the Great Satan and nothing has changed.”

It is possible to foresee a day in which an energy self-sufficient America renews its alliance with an Iranian government that has finally prioritized national interests over ideological ones. But, in the near term, it is unlikely that the largest economy in the world (the United States) is going to demote the world’s key energy producer (Saudi Arabia) to form an alliance with a country (Iran) that remains torn between resistance and reintegration.

The potential emergence of a more moderate Iranian government that improves relations with Washington raises other serious questions for Riyadh. Similar to its smaller Persian Gulf neighbors, Saudi Arabia is concerned with not only the character of the Iranian government in power but also the size and perceived “imperialist” ambitions of the Iranian nation writ large, regardless of who is governing the country. Given that much of Riyadh’s alliance with Washington is driven by mutual concerns about Iran, would the United States still court Saudi Arabia’s friendship with nuclear, economic, and military cooperation if it were no longer worried about Tehran, or would Riyadh find itself on the periphery of U.S. policy?

Confronted with warming U.S.-Iranian ties and the rest of the Gulf’s improving relations with Tehran, the Saudis have been seemingly compelled to start their own unilateral overtures, inviting Iranian Foreign Minister Mohammad Javad Zarif to visit Riyadh. But, given the ferocity of the Syria conflict and the current outlook of elites in both states, these initiatives are likely to remain limited in scope. Much will hinge on Iran’s willingness to de-escalate and diminish its involvement in the Levant to a degree that is acceptable—from a face-saving point of view—to more pragmatic elements in the Saudi regime. Yet, given the continued dominance of the more hardline Revolutionary Guards (in contrast to the more moderate Iranian foreign ministry) in hot spots like Syria, this scenario does not seem likely in the near future.

The most important obstacle to real improvement in ties is the inescapable reality of the Gulf’s structural disequilibrium. Regardless of the type of regime in Tehran, Saudi Arabia and the Arab Gulf states will continue to demand external military backing to balance what they see as Iran’s inherent hegemonic aspirations. And Iran, for its part, will continue to demand a Gulf that is free from foreign forces so that it can assert what it sees as its rightful leadership role.

In that sense, the notion of a new, more constructive equilibrium between Iran and Saudi Arabia that could facilitate a lessening of U.S. commitments in the Gulf appears more a distant dream than a short-term likelihood.