The Biden administration’s mantra for the Middle East is simple: “end the ‘forever wars.’” The White House is preoccupied with managing the challenge posed by China and aims to disentangle the United States from the Middle East’s seemingly endless and unwinnable conflicts. But the United States’ disengagement threatens to leave a political vacuum that will be filled by sectarian rivalries, paving the way for a more violent and unstable region.

The struggle for geopolitical primacy between Iran’s Shiite theocracy and the countries led by Sunni Arabs and, more recently, Sunni Turkey is stoking conflict across the region—eroding social compacts, worsening state dysfunction, and catalyzing extremist movements. Both sides have weaponized religious identity for their own purposes, using it to rally partisans and bolster their influence across the region. As a result, the broader Middle East remains a tinderbox. 

Although Iran retains the upper hand, challenges to its position are building across the region. Sunnis have tired of virulent extremism, but the anger that fueled the rise of the Islamic State (also known as ISIS) remains undiminished; new insurgencies in the broken parts of the region will undoubtedly harness that rage once more. Sunnis in Iraq, Lebanon, and Syria are increasingly chafing at moves by Tehran and its allies to tighten their hold on power. And terrorism has emerged in Afghanistan again, as the country slides into chaos in the wake of the Taliban’s victory. Without any political process to defuse these tensions, they are bound to erupt in new waves of tumult and bloodshed.

Israel’s intervention in these sectarian conflicts on the side of the Sunni powers has only added fuel to the fire. Because of Israel’s involvement, regional stability is even more subject to the fate of Iran’s nuclear program. Washington and Jerusalem are already discussing a “Plan B” for if a diplomatic settlement remains beyond reach. This path would place Iran and the United States on a collision course—as well as exacerbate sectarian tensions, deepen societal divisions, and trigger new conflicts from the Levant to Afghanistan. 

Washington’s desire to do less in the Middle East comes at a time when China and Russia are leaning into the region, a hard-line government in Iran is digging in its heels, and the Sunni Arab states are less confident than ever about U.S. security guarantees. Unless the United States paves the way for a more stable regional order—beginning by striking a deal over Iran’s nuclear program—it may find itself dragged back into the Middle East’s many conflicts despite its best efforts to walk away.


The origins of the rivalry between the Shiites and the Sunnis go back to the very beginnings of Islam, and over the centuries, the two sects have evolved distinct interpretations of Islamic law and religious practice. The strife between the two groups today, however, is rooted not in theology but in a struggle for power. Shiism and Sunnism are prominent identity markers that shape political allegiances in divided societies. The intensity of sectarian fighting has ebbed and flowed over the past two decades, but sectarianism’s salience to the region’s politics has not waned—nor has the struggle between Iran and its Sunni-led rivals, which both feeds on and fuels this schism. These two forces are different sides of the same coin.

It was the 2003 U.S. invasion of Iraq that allowed Iran to dramatically expand its influence in the Arab world. Ever since the United States brought down the authoritarian regime that guaranteed Sunni-minority rule in Baghdad, Tehran has expertly played on sectarian loyalties to empower a network of armed proxies that now stretches from Lebanon and Syria to Iraq and Yemen, forming what Jordan’s King Abdullah once called a “Shiite crescent.” In doing so, Iran has empowered Shiites at the expense of Sunnis across the region and enhanced its own influence over that of rivals such as Saudi Arabia, Turkey, and the United Arab Emirates (UAE).

The Arab world’s push for democracy and good government, the so-called Arab Spring, led autocrats, threatened by the prospect of change, to further weaponize sectarianism. Syrian President Bashar al-Assad stoked fear of Sunnis to scare the Syrian Alawite community, to which he belongs and which traces its roots to Shiism, into unflinching support for his regime. In Bahrain and Yemen, rulers justified violent crackdowns by accusing Shiite protesters of being Iranian proxies. Iran and its Arab rivals reinforced this dynamic by arraying themselves behind their respective Shiite and Sunni clients, seeing their coreligionists as tools to protect their regional influence.

Iran’s regional footprint has expanded in tandem with its nuclear program. Although the United States effectively checked Iran’s nuclear ambitions in 2015 through an internationally brokered deal, containing its regional ambitions has proved elusive. Washington’s insistence that regional matters not be included in the nuclear talks incensed its Arab allies, which were then on the losing end of sectarian proxy wars in Iraq, Syria, and Yemen. U.S. President Barack Obama reinforced their fears about Washington’s commitment to assist them in these struggles when he counseled that the Iranians and the Saudis needed “to find an effective way to share the neighborhood.”

Despite all of Iran’s recent victories, the sectarian conflicts that are racking the Middle East are far from over. 

The Sunni Arab states saw the nuclear accord as the bookend to the Obama administration’s earlier refusal to topple the Assad regime. In Arab leaders’ eyes, these two decisions tipped the regional balance of power decidedly in Tehran’s favor: the failure to topple Assad empowered Tehran’s Shiite allies in other countries, and the nuclear deal failed to restrain Iran’s regional meddling. To the Arab leaders, it seemed as if the United States was blessing Iranian hegemony in the Middle East. 

U.S. President Donald Trump was sympathetic to that view. He withdrew from the nuclear accord in 2018 and said a new deal would have to address Iran’s regional role. His “maximum pressure” campaign imposed crippling sanctions on Iran and aimed to make it impossible for Tehran to financially sustain its position in the Arab world. Under Trump, Washington took several steps to restrain Iran, including carrying out a drone strike in 2020 that killed Qasem Soleimani, the head of the Quds Force, the expeditionary branch of Iran’s Islamic Revolutionary Guard Corps, and Abu Mahdi al-Muhandis, a senior Iraqi Shiite militia commander.

The Trump administration succeeded in battering Iran’s economy, increasing social misery and political discontent. But its attempt to force a broader Iranian retreat from the Arab world failed utterly. On the contrary, Iran responded by escalating regional tensions: it attacked tankers in the Persian Gulf, targeted oil facilities in Saudi Arabia, and launched an audacious missile strike on Iraqi air bases that housed U.S. troops, bringing Iran and the United States closer to war than ever before.

Iran emerged from the Trump years more aggressive and lethal. Since the United States left the nuclear deal, Iran has increased its stockpile of enriched uranium, expanded its nuclear infrastructure, and gained critical nuclear know-how. It is now perilously close to possessing enough fissile material for a nuclear bomb.

It was the decision to scrap the nuclear deal, not the decision to sign it in the first place, that has made Iran a larger force in the region. Tehran’s nuclear and regional ambitions have advanced hand in hand: a credible nuclear program provides an umbrella that protects its proxies across the region, which in turn boost Iran’s influence further. Thus, the more expansive and resilient the nuclear umbrella, the more effective the proxies that operate under its protection. By reducing the scope of Iran’s nuclear program, the 2015 nuclear deal also reduced the protection Tehran could provide its proxy forces. With the deal in abeyance and Iran rapidly growing its nuclear program, its regional forces will become more brazen. 

Iranian President Ebrahim Raisi addressing the UN General Assembly in New York, September 2021
Iranian President Ebrahim Raisi addressing the UN General Assembly, New York, September 2021
Eduardo Munoz / Reuters

Iran’s hard-liners also consolidated their power during the Trump years. They saw their worldview vindicated by the “maximum pressure” campaign: to them, it constituted proof that the United States was pursuing regime change in Tehran and would not relent until the Islamic Republic collapsed. This rendered engagement with Washington futile and meant that Iran could secure its interests only through confrontation with the United States and its allies. Iran thus emerged from the Trump era determined to continue with its nuclear program and strengthen its position in the region. 

Ebrahim Raisi, Iran’s new president, made it clear during his speech to the UN General Assembly in September that he believes the regional balance of power is tilting in Tehran’s favor. Evoking the January 6 riot at the U.S. Capitol and the images of Afghan civilians falling from U.S. aircraft fleeing Afghanistan, Raisi said these scenes sent a clear message to the world: “The United States’ hegemonic system has no credibility, inside or outside the country.” 

As such statements suggest, Iran’s new government has adopted a triumphalist perspective on events in the Middle East. In its view, Iranian intervention in Syria saved Assad in the face of a concerted American, European, Turkish, and Sunni Arab push to topple him. In Yemen, a brutal U.S.-backed Saudi military campaign failed to change the reality that the Houthis are firmly entrenched in the capital of Sanaa and almost all of the country’s north. Iran has also sustained its dominant position in Iraq and Lebanon, despite economic pressures and what it views as meddling from its rivals.

The imperative of maintaining Iran’s influence in the Arab world is now embedded in the strategic calculus of the country’s deep state, and the militias that Tehran has built for that task are facts on the ground across the region. But despite all of Iran’s recent victories, the sectarian conflicts that are racking the Middle East are far from over. 

Primed to explode

Iran is hardly the only party behind the rise of sectarian conflict across the Middle East. Qatar, Saudi Arabia, Turkey, and the UAE have all supported Sunni factions in the Arab world. Turkey and wealthy Sunni businessmen in the Persian Gulf have funded some of the more extreme Sunni factions that sought to topple Assad—including ISIS. That group’s virulent anti-Shiism and its promise to resurrect the Islamic caliphate, which served as the seat of Sunni power in earlier eras, appealed to disenfranchised Sunnis in the expanse that stretches from Damascus to Baghdad. In the end, ISIS was undone by an alliance of convenience formed by Russia, the United States, and Iran, the last of which fought ISIS alongside its local Shiite allies in Iraq and Syria. 

But although Tehran has so far been able to come out on top in the regional struggle for influence, it may find itself under increasing pressure in the years ahead. The Sunni Persian Gulf monarchies, along with Israel and Turkey, all have a stake in the outcome of the sectarian conflicts racking the Arab world. With the United States signaling that it will not try to dislodge Iran from the various places where it has entrenched itself, regional actors are preparing to take up the gauntlet. 

In Syria, the Assad regime is attempting to consolidate its authority, but the country remains a sectarian powder keg. Fighting could resume over control of the northwestern governorate of Idlib and the Kurdish-controlled region in the northeastern part of the country. Turkey has pushed back against Assad’s attempts to take over Idlib, bolstering its claim to be the defender of Sunni rights in Syria. Israel has also been drawn into the vortex of the Syrian conflict, as it grows increasingly uneasy with Iran’s expanding military footprint there. Meanwhile, the country’s majority Sunni population, which lives in the parts of the country devastated by the decadelong war, remains disenfranchised and impoverished. 

Without a new security arrangement, chaos and conflict will be the order of the day in the region.

The fate of Syria is tied to that of Iraq. The central Iraqi government’s victory against Sunni jihadis served only to underscore its dependence on military support from Iran and the United States and also came at the cost of bolstering the influence of the country’s Shiite militias. The Iraqis have managed to temper sectarian conflict for now, but its embers are glowing bright just below the surface. Recent national elections also highlighted the tenuousness of the political status quo. In advance of voting in October, the influential Grand Ayatollah Ali al-Sistani and the Shiite religious establishment encouraged Iraqis to head to the polls—but those pleas fell on deaf ears. Public apathy resulted in record-low turnout, which gave a boost to the most sectarian political figures in the country: the maverick cleric Muqtada al-Sadr and former Prime Minister Nouri al-Maliki. The only silver lining was that the parties affiliated with Iranian-backed Shiite militias also did poorly. That has, however, given them a motive to destabilize the country—as shown from a recent attempt to assassinate the country’s prime minister.

Sadr’s ascension does not augur well for sectarian peace in Iraq. Although he has fashioned himself as a nationalist, he equates Iraq’s national interests with his Shiite community’s right to rule the country. His militia was at the forefront of the sectarian civil war that engulfed Iraq in 2006, and he does not intend to cede power to assuage Sunnis. Although he wants autonomy from Iran, he will be confronted with rival factions at home and maneuvering from the Sunni monarchies of the Persian Gulf, who have opposed Shiite control of Iraq. So his inclination will be to rely on Tehran.

The growing tumult in Lebanon also portends instability, but not a lessening of Iranian influence. The country’s dominant political actor is Hezbollah, which has built up its military capacity over the years with generous Iranian backing. The Lebanese Shiite paramilitary group has performed well in wars against Israel, and its vast arsenal of missiles remains a menacing deterrent to Israeli military action against Iran. Hezbollah has also successfully deployed its fighters on behalf of Iranian allies across the Arab world, notably in Iraq and Syria, becoming even more indispensable to Tehran. 

Protesting deteriorating living conditions in Beirut, November 2021
Protesting deteriorating living conditions in Beirut, November 2021
Mohamed Azakir / Reuters

But Hezbollah is also a political force in Lebanon, complicit in the economic crisis that has corroded the country’s state and society. The country’s Christian and Sunni communities have long decried Hezbollah’s pro-Iran loyalties and insistence on functioning as a state within a state. Growing numbers of Lebanese now blame the group for undermining the official investigation into the devastating blast at the Beirut port in August 2020, which destroyed large parts of the city. Hezbollah will not relinquish power without a fight; its hold on the Shiite community remains strong, and Iran is committed to supporting the organization. Lebanon has long been prone to paroxysms of violence, and it is not hard to see how current events are setting the stage for another bout of sectarian conflict there. 

In Yemen, a civil war has become a proxy war. On one side is the central government, which is backed by Saudi Arabia. On the other are Houthi tribespeople, who hail from the country’s north, which is dominated by members of the Zaidi Shiite sect, and who enjoy support from Iran. The war took on an overtly sectarian cast in 2015, when a coalition of states led by Saudi Arabia and the UAE intervened to prevent a Houthi victory and the establishment of an Iranian beachhead on the Arabian Peninsula. Their campaign has devastated Yemen—but it has not vanquished the Houthis, whose reliance on Iran has only grown during the fighting. When the war ends, the Houthis will hold sway over significant parts of Yemen and will have a large say in its politics. The glass will be half full for Iran and the Shiite side of the regional ledger and half empty for Saudi Arabia and its Sunni allies. 

As the Sunni Arab states look to even the playing field, they are increasingly warming to a powerful ally in the struggle against Iran: Israel, which has placed itself squarely in the middle of the burgeoning regional tussle by launching air raids against Iranian bases in Iraq and Syria and carrying out assassinations, cyberattacks, and industrial sabotage to slow the Islamic Republic’s nuclear program. Tehran has thus far limited its responses against Israel to cyberattacks and attacks on its ships in the Persian Gulf, but the situation could quickly escalate—not necessarily into direct war between Iran and Israel but perhaps to clashes between both side’s tacit partners in Iraq, Lebanon, and Syria and to Iranian attacks against Israel’s new allies in the Persian Gulf. 

The Sunni Backlash

In the midst of all of this, the Sunni Arab states are in search of new strategies to protect their interests. They have thus far relied on the United States to contain the expansion of Iran’s regional influence, an expansion Washington itself set in motion when it invaded Iraq. But the U.S. departure from Afghanistan, talk of a reduced U.S. military presence in Iraq, and the Biden administration’s desire to end the “forever wars” have compelled Saudi Arabia and the UAE to start talking to Iran in the hopes of reducing tensions and buying time to build their own regional capabilities.

These talks have come after years of proxy wars across the region, Saudi and UAE support for the American strangulation of Iran’s economy, and Iranian attacks within Saudi and UAE territory. They therefore represent an important effort to reduce tensions. Saudi Arabia wants Iran to lean on the Houthis to end the war in Yemen and to bring an end to drone attacks on its territory. Iran, in turn, wants full normalization of relations with Saudi Arabia. A breakthrough is not close at hand, largely because the talks are happening in the shadow of nuclear negotiations between Iran and the United States. The two sides continue to meet, however, and have identified potential first steps in a rapprochement, such as the opening of consulates to facilitate religious tourism. The Biden administration has supported the dialogue, but Washington cannot push Riyadh to reach a deal with Tehran if it cannot do so itself. 

The specter of Sunni extremism also continues to worry Iran. The Taliban’s victory was a boon for Sunni militancy across the region: the Afghan group’s history is mired in bloody sectarian violence, and it sees Shiism as outside the pale of Islam. Although the Taliban no longer openly espouse hostility to Shiism and have forged ties with Iran, their return to power has been marked by a purge of Shiite Hazaras from government jobs, the closure of their businesses, and their expulsion from their homes and villages. Although the latest sectarian violence in the country, such as the deadly bomb attacks on Shiite mosques, has been blamed on an ISIS affiliate known as Islamic State Khorasan, or IS-K, it still underscores the potential for a wider sectarian conflict in Afghanistan. 

Washington cannot push Riyadh to reach a deal with Tehran if it cannot do so itself.

The Sunni Arab states are also seeking strategic depth by mending fences with Turkey, which under President Recep Tayyip Erdogan considers itself to be a regional power and a defender of Sunni prerogatives. Erdogan’s Turkey sees itself as the heir to the Ottoman Empire, which until 1924 was the seat of the Islamic caliphate, the symbolic heart of Sunni power. It also maintains close ties to the Muslim Brotherhood, the Arab world’s most important Islamist force. During the Arab Spring, Turkey fashioned itself as the model for the Arab world, supporting popular demands for democracy and the Muslim Brotherhood’s ambitions for power. Later on, it also took Qatar’s side when its Persian Gulf neighbors imposed a blockade on it.

These policies angered the Persian Gulf monarchies, which perceived Turkey as a rival for leadership of the Sunni world. This internecine bickering even at times overshadowed the sectarian rivalry with Iran; in fact, Ankara’s relationship with Tehran has generally been warmer than its ties with Riyadh and Abu Dhabi. Turkey’s competition with its Sunni rivals has brought it into every arena in which sectarianism is at play, as Erdogan’s government has staked its claim to influence in Iraq, Lebanon, and, most recently, Afghanistan.

Turkey has been a bulwark against Iran’s influence. Turkey has used its military muscle in Iraq and Syria effectively: although it cannot match Iran’s proxy power, its military, economic, and diplomatic capabilities have ensured that it maintains an influential role in the Middle East. The Sunni Arab states, by comparison, have failed to check Iranian power in any meaningful way. Their investment in the Syrian opposition came to naught, and Saudi Arabia abandoned Lebanon, failed to gain a foothold in Iraq, and has stumbled in the war in Yemen. The Sunni Arab states, however, continue to exercise influence in Washington, and they are bolstering that strategic depth with intelligence and military cooperation with Israel. But on the ground, they can only hope to slow Iran’s progress, not reverse it. 

leaving on good terms

The United States cannot mitigate all the dangers looming in the Middle East. But it should avoid making things worse. A smaller American role in the region may be inevitable, but the way in which Washington pulls up its stakes will matter. To many in the Middle East, American withdrawal is a shorthand for Washington abandoning the region, where it has previously defended against threats from the Soviet Union, Iran, Iraq, and, most recently, ISIS. Even if the United States continues to maintain a large military presence in the region, its commitment to using military force is increasingly open to question. 

That strategic confusion is an opening for Iran and its proxies. It will also invite new entrants into the fray, such as Russia and Turkey. There is no ready substitute for the United States’ containment strategy, which for over four decades has served as the region’s de facto security architecture. The best Washington can aim for is to discourage regional rivalries from intensifying, in the hope that relative calm could provide an opportunity for new regional frameworks to develop. For this reason, U.S. efforts to back away from enforcing containment must go hand in hand with a diplomatic surge to diminish and resolve conflicts between regional powers.

A nuclear deal with Iran remains the most important deterrent to greater regional instability. There are understandable reasons why the Biden administration may be hesitant about returning to the 2015 nuclear deal. Some of the accord’s restrictions on Iran are set to expire before the end of President Joe Biden’s first term, and the lifting of sanctions that is required as part of the deal would invite a maelstrom of bipartisan criticism. For these reasons, the administration says it wants a “longer and stronger” deal. Iran, however, is interested only in a restoration of the 2015 deal—but this time with American guarantees that the next administration will not upend the deal again. A deadlock—or, worse, the collapse of talks—would put Iran and the United States on a dangerous path to confrontation that would inevitably embroil the Arab world and inflame sectarianism. 

The root cause of the Middle East’s troubles remains unresolved.

The Biden administration has encouraged regional actors to talk to one another. But these dialogues will not be sustained if the effort to restore the nuclear deal falters. The first victim will be stability in Iraq and Lebanon, which requires consensus among Shiite and Sunni stakeholders. For the Biden administration to extricate the United States from the Middle East, it needs to establish a modicum of regional stability—and that effort must begin with returning Iran and the United States to mutual compliance with the 2015 deal. 

For over four decades, the United States saw the Middle East as vital to its national interests. It built alliances with Arab states to contain Iran, keep Islamism at bay, and manage the Israeli-Palestinian conflict. The American strategy was most successful when it was able to maintain a stable balance of power between Iran and its Arab neighbors. Ever since the United States undermined that balance by invading Iraq in 2003, it has been trying to restore it—and now, faced with other urgent global challenges, it is abandoning the effort altogether. There is ample reason to embrace this strategic recalibration. It is too costly to pursue an elusive balance of power, especially since the Middle East is no longer as vital to American national interests. 

But leaving the region to its own devices is a dangerous gambit. Without a new security arrangement, chaos and conflict will be the order of the day. A recrudescence of Islamic extremism, the specter of further state collapse, wars large and small over territory and resources, and open conflict between Iran and Israel will have catastrophic security and humanitarian consequences that will inevitably demand renewed U.S. attention. If the United States wants to shrug off the burden of sustaining the Middle East’s balance of power, then it should look for a sustainable alternative—an arrangement that can end the region’s most dangerous conflicts and set in place rules of the game for a workable regional order. That task must start with defusing the conflict that represents the greatest threat to the region: the standoff with Iran.

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  • VALI NASR is Majid Khadduri Professor of Middle East Studies and International Affairs at the Johns Hopkins University School of Advanced International Studies.
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