The attack, which Khamenei had publicly praised as an “epic victory,” marked a crescendo of four decades of Iranian efforts to train and arm a network of nonstate militant groups as a way to threaten its enemies and extend its influence in the Middle East.

But behind closed doors, the Iranian leader told senior Hamas representatives, along with Lebanese, Iraqi, Yemeni and other Palestinian militia leaders, that Tehran had no intention of directly entering the conflict and widening the war, according to two high-ranking officials from Hamas and two from Hezbollah. Side battles, he told the delegates, risked distracting the world from Israel’s devastating incursions in Gaza. The message: Hamas was on its own.

Now the axis faces a moment of truth. As Iran’s allies stoke even more fires across the region—from attacks on shipping in the Red Sea to Sunday’s drone strike that killed three U.S. troops in Jordan—they are pushing their benefactor closer to the brink of a direct conflict with Washington that it has long sought to avoid.

Iranian military and financial power forms the backbone of the alliance, but Tehran doesn’t exert full command and control over it. Not every member shares Iran’s Shiite ideology, and all the groups have domestic agendas that sometimes conflict with Tehran’s. Some operate in geographically isolated areas, making it tricky for Iran to provide weapons, advisers and training. That includes Hamas, which is a Sunni movement, or the Houthis in Yemen, whose attacks on shipping have upended global trade flows and triggered U.S. and U.K. counterstrikes.

U.S. officials blamed Sunday’s drone strike on an Iran-backed group, and the White House on Monday said it believed the perpetrators were supported by Kataib Hezbollah, an Iranian militia ally based in Iraq, with forces in Syria. President Biden said he was weighing how to retaliate. Iran rejected any involvement.

For Tehran, the power of the axis lies in the plausible deniability that comes from each member’s operational and territorial autonomy. Iran gets to distance itself from the militias even as they serve Iran’s strategic interests, countering U.S. and Israeli power in the region.

The approach has allowed Tehran to avoid sweeping retaliation from Israel and the U.S. that might destabilize its clerical rule, said Norman Roule, a former Middle East expert with the Central Intelligence Agency. Iranian aggression, he said, “now invariably involves actions that are attributable to Tehran but which Iran can deny sufficiently.”

The Oct. 7 attack is testing that model like never before. In dealing the biggest single blow ever to Israel—killing more than 1,200 people, most of them civilians—the assault has triggered a massive Israeli military campaign aimed at eradicating Hamas. Israel has laid waste to swaths of the Gaza Strip and targeted Hamas leaders, most brazenly in an airstrike in Beirut in January that killed Saleh al-Arouri, the group’s political deputy, who weeks earlier had participated in the meeting in Tehran with Khamenei.

That has created a major dilemma for Tehran: Come to the defense of its Palestinian ally, risking a regional war that could engulf Iran proper, or stand aside and watch the potential decimation of a vital partner in the alliance?

“What happens if Hamas is completely eliminated? And then, if they are eliminated, would not that mean that the balance of power has shifted to Israel’s favor?” a senior Hezbollah official said. He described the Oct. 7 assault as a “catastrophic success.”

The attack served Tehran’s interests, pausing a diplomatic rapprochement between Israel and Saudi Arabia—another regional rival—and allowing Iran to cast itself as the champion of the Palestinian cause.

Iran’s leadership moved to head off any retaliation by Israel or the U.S. by swiftly denying any involvement in the planning or execution of the assault. Hamas and Hezbollah officials offered conflicting accounts of Iran’s possible prior knowledge. The Wall Street Journal has reported that some Hamas and Hezbollah officials said Iranian security officials greenlighted the attack, noting that others questioned that account.

In either case, the attack couldn’t have happened without many years of Iranian support for Hamas in the form of weapons, money and training, said Afshon Ostovar, an associate professor at the Naval Postgraduate School in Monterey, Calif., who specializes in Iran’s military ventures in the Middle East.

“Whether they move in lockstep in this action or that action is less important than how they move collectively over time,” Ostovar said. “Iran armed them to do this: to take the war to Israel in a way that Iran couldn’t.”

The axis rises

The axis of resistance was born out of Iran’s quest to expand its military and ideological influence across the Middle East after the 1979 Islamic Revolution. The network of extremist militant groups it built took advantage of weak states and instability to gain military and, often, political power. Spanning Iraq, Syria, Lebanon, Yemen and the Palestinian territories, the alliance allowed Iran relative freedom of movement from Tehran to the Mediterranean and the Red Sea.

In 1982 the Quds Force, an arm of the Islamic Revolutionary Guard Corps, began fostering relations with young Lebanese militants during the chaos of Lebanon’s civil war, training and arming them to harass Israeli soldiers and wage guerrilla warfare. The militia that emerged, Hezbollah, became Iran’s most potent ally, training Palestinian groups, including Hamas and Palestinian Islamic Jihad, as Iran funneled financial aid and weapons to them.

Qassem Soleimani, a charismatic Iranian commander, took over the Quds Force in the late 1990s. He channeled money, weapons and military advisers to prop up a string of Shiite militias in Iraq after the U.S. invaded the country in 2003. The militias killed more than 600 U.S. soldiers, according to the U.S. Justice Department. Soleimani rose to prominence across the region as the mastermind of Iran’s shadow wars.

As Soleimani won the trust of marginalized Shia groups in Iraq, he also deepened Iran’s relations with Hamas, which stretched back to the early 1990s. The Palestinian group needed a foreign sponsor willing to circumvent the international sanctions imposed on it after winning elections in Gaza in 2006. Iran helped smuggle rockets and other military equipment to Hamas through tunnels from Egypt. After Egypt cracked down, the Quds Force helped Hamas develop domestic weapons capabilities.

Iran’s allies, while dependent on Tehran, all had agendas of their own, which at times tore at the seams of Soleimani’s axis. Yemeni Houthi rebels seized the country’s capital, San’a, against Iranian advice. Iraqi militia leader Qais al-Khazali once defied Iranian orders not to attack U.S. forces, saying “the Americans occupy our country, not yours.” Hezbollah, as it became one of Lebanon’s largest political parties, was forced to balance voter demands at home with Soleimani’s plans for the militia abroad.

During Syria’s civil war, Soleimani deployed Hezbollah, along with militias of Iraqis, Afghans and others, to help defeat a rebellion against President Bashar al-Assad. That put Soleimani’s forces at odds with Hamas, which supported the mostly Sunni uprisings of the Arab Spring. Hamas trained Syrian rebels in guerrilla-warfare tactics, and its members were among the many who disappeared into Assad’s prison system.

Differences were ironed out after Yahya Sinwar, a senior Hamas official, took the helm in Gaza in 2017 following his release from Israeli jail in a 2011 prisoner swap. Sinwar, who according to his former Israeli interrogator had reached out to Iran while in prison, shifted Hamas’s focus in Syria and dispatched a delegation to Tehran to mend ties. Hamas also held a public reconciliation meeting with Hezbollah chief Hassan Nasrallah, though some friction persisted between the two groups.

By pulling Hamas closer, Iran was trying to turn the page on the sectarian wars in Syria and Iraq and gain legitimacy across the region as an advocate of the Palestinians, said Mohanad Hage Ali, deputy director of research at the Malcolm H. Kerr Carnegie Middle East Center in Beirut, who has studied Iran’s network of militias for nearly three decades.

The road to Oct. 7

In early 2020, Soleimani was killed in a U.S. drone strike outside Baghdad’s international airport. The U.S. and Israel hoped the death of Soleimani, who had assumed an almost mythical status among his followers, would curtail the Quds Force as a regional power. That didn’t happen.

Soleimani’s successor and longtime deputy, Esmail Qaani, was less well-known to the public, but he quickly stepped into the role.

“The Quds Force is an enterprise and he is the CEO. At the end of the day, he’s the guy who pays their salaries,” Ostovar said of Qaani.

Under Qaani, Iran increasingly began to promote the idea of a unified front with its militia allies. Palestinian groups became more closely aligned internally as well. Under Hamas leadership, nearly a dozen Palestinian groups began conducting wargames exercises, overseen and publicized on a channel on the Telegram messaging app. Israeli intelligence noticed the exercises but didn’t take them seriously, according to current and former Israeli security officials.

In May 2021, Israeli police forces stormed the compound of the Al Aqsa Mosque in Jerusalem, firing tear gas and stun grenades after clashes with Palestinians protesting the eviction of residents in the eastern part of the city. The conflagration at Al Aqsa, a mosque that is central to both Shia and Sunni Muslims, prompted widespread regional condemnation of Israel.

In a speech broadcast on Al Jazeera, Sinwar warned “the multitudes of our people and nation will set out, cross the borders, and swarm like a flood to uproot your entity.” Sinwar added that Hamas was grateful to Iran in providing money, weapons, and expertise over the years, adding: “They have supported us in everything.”

In late 2021, Hamas officials met with Hezbollah leader Nasrallah and his deputy, Naim Qassem, in Beirut to discuss ways to retaliate against Israel for the storming of Al Aqsa, according to the two Hamas and two Hezbollah officials. Iranian security officials didn’t participate in the meeting, the officials said.

Meanwhile, animosity between Israel and Iran was heating up. In May 2022, an Iranian commander in charge of a Quds Force unit tasked with kidnapping and killing Israelis abroad was shot dead on the street in Tehran.

His was the latest in a string of assassinations in Iran presumed to be the work of Israel, including the killing two years earlier of Mohsen Fakhrizadeh, regarded as the father of Iran’s nuclear-weapons program. Israel hasn’t confirmed or denied any involvement.

The rash of assassinations piled pressure on the Quds Force to respond. That summer, officials from Hamas, the Quds Force and Hezbollah met regularly to draft scenarios to attack Israel, including one from Gaza, one from south Lebanon and one from Syria, the latter of which was quickly ruled out, according to the two Hamas and two Hezbollah officials. A fourth option involved simultaneous infiltrations from south Lebanon, Gaza and the West Bank, the officials said. Another senior Hamas official said general plans for action against Israel were discussed, but no timing was set for an attack.

In the spring of last year, five Revolutionary Guard commanders were killed in an Israeli airstrike in Syria, among them an adviser to Qaani. The Quds Force commander held a series of meetings with militant leaders across the region with the aim of launching a fresh wave of attacks on Israeli targets, the Journal reported at the time. One of the meetings, which was also reported in Lebanese and Israeli media, was held at the Iranian Embassy in Beirut and attended by Qaani, Hezbollah leader Nasrallah, Hamas political leader Ismail Haniyeh and al-Arouri, his deputy.

Hezbollah had come to play a central role in coordinating activities in the alliance, particularly since the killing of Soleimani. It had helped the Revolutionary Guard train militias to fight Islamic State in Iraq and Syria, where military bases usually housed Iranians on one floor and Hezbollah on another, a Hezbollah security insider said. It also allowed Palestinian militants to fire at Israel from territory Hezbollah controlled in southern Lebanon.

“This year, more than ever, we have seen the axis of the resistance be strong, capable and cohesive, as we have seen on the ground in recent weeks,” the Hezbollah chief said in a speech last spring after Palestinian militants fired a barrage of more than 30 rockets at Israel, the largest such attack from Lebanese soil since the country’s 2006 war with Hezbollah, although his group claimed not to have been informed beforehand.

Iran, meanwhile, was growing concerned about a broader diplomatic realignment in the Middle East, after Israel in 2020 had signed a watershed agreement known as the Abraham Accords with the United Arab Emirates and Bahrain to normalize diplomatic relations. The deal was meant to reset regional power dynamics and sideline Tehran. An even bigger agreement was now in the works between Israel and Saudi Arabia in what would be the most momentous Middle East peace deal in a generation.

Iran worried that Israel’s deals with Arab nations would allow it to expand its influence in the region. In internal discussions, the Quds Force vowed to spoil normalization efforts, according to an Iranian official and an adviser to the Guard. Quds officials feared a rapprochement would limit the axis in carrying out attacks on the Arab Peninsula or the Red Sea, where the Houthis and the Revolutionary Guard routinely have hijacked vessels and disrupted global shipping, said the Iranian official and the Guard adviser.

By September, Israeli intelligence began to detect an uptick in hostility from Palestinian militants, including Hamas, which posted a video showing a drill for a commando operation that included an amphibious attack using divers. Hamas even constructed a replica of an Israeli kibbutz and trained to storm it in full view of Israeli security forces—a scenario eerily similar to what would happen on Oct. 7.

Still, Israel remained convinced that the real threat was on its northern border. “We could see these exercises, but they repeated them every two months. We thought this was just a statement reiterating their stand as a resistance movement,” said an Israeli official.

In a speech on Oct. 3, Khamenei, the Iranian supreme leader, warned Arab governments trying to mend ties with Israel that they were making a mistake. Khamenei told an Islamic unity conference in Tehran that “resistance forces throughout the region” would eradicate Israel. “Defeat awaits them,” he said.

The attack

In the early hours of the morning on Oct. 7, a barrage of at least 3,000 rockets rained over Israel in the span of about 20 minutes.

Nearly 3,000 Palestinian militants, most of them Hamas members, breached the barrier from Gaza on pickup trucks, motorcycles and in paragliders. Heavily armed and in black fatigues, they entered kibbutzim in the south and gunned down unarmed civilians, recording the atrocities with body cameras. They burned Israeli military vehicles and stopped cars on highways, executing drivers and passengers. At an outdoor music festival near Re’im, militants embarked on a massacre and killed at least 360 participants. When they left, Hamas and Palestinian Islamic Jihad members took more than 200 hostages with them into Gaza. It was the most serious breach of Israel’s borders since the 1973 Yom Kippur War.

The scope and scale of the attack left governments around the world wondering how Hamas managed to blow through the defenses of one of the Middle East’s most powerful militaries, despite having been under a strict blockade for nearly two decades.

American intelligence agencies maintain that while Iran likely knew that Hamas was planning operations against Israel, it didn’t know the precise timing or scope of the Oct. 7 attack. Israeli intelligence agencies also say they don’t have evidence of direct Iranian involvement in the attack.

The Journal reported that Iranian security officials had given the green light for the assault at a meeting in Beirut the week before, on Oct. 2, citing senior Hamas and Hezbollah officials, who also said officers of the Revolutionary Guard had worked with Hamas since August to devise the attack. Those officials and an additional high-ranking Hamas member continue to stand by those assertions.

Other Hamas and Hezbollah officials, however, have contended that all details about the attack, including the scope and the date, were kept tightly under wraps by the military wing of Hamas.

“Everyone was aware of the need to carry out an extraordinary action,” Husam Badran, a senior member of Hamas’s political wing based in Doha, said in an interview. But “details of the military operation were up to the Qassam Brigades,” he said, referring to the military wing.

Some parties to the alliance have an interest in expanding the war by drawing Iran into it, while others, including Iran itself, seek to prevent further escalations. The compartmentalized nature of the alliance members’ interactions may mean that even senior officials don’t always have a complete picture of events.

The aftermath

While Iran initially hailed the Oct. 7 attack as a tremendous victory for its axis of resistance, its leaders quickly distanced themselves from any notion that it had been involved.

Other allies also denied prior knowledge. Hezbollah chief Nasrallah was angered by news of the attack, according to a Western official who speaks to senior Hezbollah figures. After remaining silent for nearly a month, Nasrallah delivered a speech insisting that Hezbollah hadn’t taken part. He said the time wasn’t right for Hezbollah to wage all-out war with Israel but warned that calculation could change.

The U.S. warned Iran, publicly and through the Swiss Embassy in Tehran, which handles U.S. interests in the country, that it would retaliate against any aggression. Iran told the U.S. that it couldn’t control how its allied groups across the region would react to the Israeli offensive in Gaza, said a person briefed on the Swiss backchannel, and that, “those groups may take it upon themselves to escalate if there is no cease fire.”

Quds Force commander Qaani shuttled between Iran, Syria and Lebanon to try to keep actions by Iran’s allies from spiraling out of control, according to a Western security official, a senior Lebanese official and the Revolutionary Guard adviser.

From Lebanon, Palestinian groups and Hezbollah shot missiles and small-arms fire at northern Israel, hitting population centers, forcing Israel to evacuate towns and displacing tens of thousands from the border area.

The Houthis in Yemen, in a rare intervention against Israel, fired rockets at the southern Israeli city of Eilat and attacked Israeli-linked vessels in the Red Sea.

In recent weeks, the Houthis have launched fresh attacks against commercial ships around Yemen, including a missile strike on the Gibraltar Eagle, a U.S. bulk carrier. The U.S. and the U.K. have responded with airstrikes on Houthi positions inside Yemen. The Biden administration said it would again designate the Houthis as a terrorist organization, following years off its terror list.

The exchanges have rattled global markets, upended international shipping routes and pulled the Biden administration into a wider conflict that risks exacerbating regional tensions. Still, the calculated skirmishes have steered clear of a direct confrontation between Iran and the U.S., stopping short of a full-blown regional war.

After the deadly drone strike on U.S. troops in Jordan Sunday, the Biden administration said it would respond forcefully against the perpetrators.

“But we don’t seek a war with Iran,” National Security Council spokesman John Kirby told CNN Monday. “We’re not looking for a wider conflict in the Middle East.”

Analysts say that the Hamas attack went against the way Iran for four decades has kept the conflict against its enemies at low intensity to avoid retaliation that could topple the Islamic Republic.

“Iran has survived for so long, unlike Saddam Hussein and other authoritarian regimes, because they understand the balance of power in the region,” said Hage Ali, of Carnegie in Beirut. He called Iran’s strategy one of “long-term attrition.”

The attack has also hurt Iranian interests. A monthslong truce collapsed between Iranian-backed militias and U.S. forces in Iraq and Syria. The U.S. held up the delivery of $6 billion in funds it had parked in Qatar as part of a prisoner swap that was completed in September, and any hopes Tehran had of further relief from sanctions imposed on its nuclear program appear extremely slim for now.

“They got trapped at their own game,” said the Western security official.

When Hamas political chief Haniyeh and his deputy Arouri in November traveled to Tehran for a meeting with Khamenei, they were told the Islamic Republic supported Hamas but didn’t play any role in the militants’ surprise attack on Israel, according to Iranian state media.

Haniyeh and Arouri left the meeting disappointed but provided Iran with a list of weapons they might need if the war continues beyond six months, including antitank missiles and shoulder-fired surface-to-air missiles, Hamas officials said.

Shortly after the meeting, according to senior Hamas and Hezbollah officials, a larger gathering of Iran’s allies took place in Tehran. Attendees included Haniyeh and Arouri as well as Quds Force commander Qaani, senior Hezbollah official Hashem Safi al-Din, Houthi ambassador to Tehran Ibrahim al-Dulaimi and Palestinian Islamic Jihad leader Ziyad al-Nakhalah.

In the meeting, Khamenei told the group he was aware of growing discontent with Nasrallah’s speech saying the time wasn’t right for a wider conflict, the Hamas and Hezbollah officials said. Khamenei defended the strategy of avoiding an all-out war, saying that he didn’t want to take away attention from the Palestinian struggle, which he said was playing out in Hamas’s favor despite the continuing losses in Gaza, the officials said.

Iran had built its axis of resistance to ensure its own survival, not that of Hamas. While the Palestinian group is an important ally, Iran wasn’t going to risk the destruction of its strongest partner, Hezbollah, to save it, said Emile Hokayem, an expert on security and nonstate actors in the Middle East with the International Institute for Strategic Studies.

“They’re not going to deploy Hezbollah in a war the Iranians don’t see as existential,” he said.