Editor’s Note: Arman Mahmoudian is an expert on the so-called ‘Axis of Resistance’ – non-state militant groups that have been supported by Iran and share an anti-Israel and anti-U.S. ideology. He is a frequent contributor to Stimson on these topics and has written presciently about the dynamics leading up to Hamas’s Oct. 7 attack on Israel.
By Barbara Slavin, Distinguished Fellow, Middle East Perspectives
Iran enters 2025 with its large network of state and non-state allies – built up painstakingly over nearly half a century — severely damaged.
Iran has sponsored and funded this network running from Lebanon to Yemen, Gaza to Iraq, not only to project power but also as a deterrent against its primary adversaries, the United States and Israel. However, events beginning with Hamas’s devastating attacks on Israel on October 7, 2023, have boomeranged in spectacular fashion, decimating key figures and structures within the alliance.
The oldest member of the so-called Axis of Resistance and the cornerstone of Iran’s regional strategy was the Syrian regime of the Assad family. Syria was one of the first countries to recognize the Islamic Republic of Iran after the 1979 revolution, among Iran’s top suppliers during the 1980-88 Iran-Iraq War, and one of Iran’s very few friends in the Arab world. Iran returned the favor by mobilizing support for the Assad regime following the 2011 April Spring uprising and with Russian help, enabled the regime to keep control over much of the Syrian heartland. However, in December 2024, the regime collapsed after an 11-day offensive by Hay’at Tahrir al-Sham (HTS), a Turkish-backed Sunni Muslim militia from Idlib, which had remained in rebel hands. Billions of dollars in Iranian investment evaporated seemingly overnight and Iran lost its premier gateway to the Arab world.
It was through Syria in 1983 that Iran sent a division of its newly formed Islamic Revolutionary Guard Corps (IRGC) to Lebanon, laying the foundation for the creation of Hezbollah, the most potent non-state actor in the Axis of Resistance. For decades, Syria facilitated the transfer of weapons, resources, trainers, and troops from Iran to Lebanon, ensuring Hezbollah’s operational strength as it grew to dominate the Lebanese state and support Iran-backed militants from Iraq to Yemen.
The loss of Syria as a strategic ally is a severe blow to the Axis of Resistance. Without Syria as a land link, the Axis faces significant logistical and strategic challenges, threatening its cohesion and effectiveness.
The fall of the Assad regime also threatens Hezbollah’s position in Lebanon. With Syria under the influence of a Sunni militant group, there is the possibility of a Sunni insurgency against Hezbollah in Lebanon.
Hezbollah’s decision to open a second front against Israel after the October 27, 2023, Hamas attacks, instead of restraining Israeli actions in Gaza, led to a full-scale second Israel-Lebanon war. Hezbollah suffered catastrophic losses: its entire high command was eliminated, thousands of its troops were killed, and a significant portion of its arsenal was destroyed. For Iran, rebuilding Hezbollah is an urgent priority. However, it is unclear how Iran can accomplish this goal without Syria as a conduit.
The events of October 7, 2023, have also had a devastating impact on one of the least compatible members of the Axis, Hamas. The Sunni radical militants of Gaza have long been an inconvenient ally for Shi’ite Iran. During the Syrian civil war, for example, Hamas openly sided with Assad’s opponents, and its leaders have publicly criticized Shi’ite Islam, dismissing it as a “false branch” of Islam. Yet, Iran continued to support Hamas due to a shared perception of mutual threats from Israel and the United States.
In the past 15 months, however, Israel has eliminated Hamas’s military leadership, including Yahya Sinwar and Mohammed Deif, and assassinated its political leader Ismail Haniyeh in Tehran. Israel’s large-scale ground invasion of Gaza, coupled with a bombing blitz, has turned much of the enclave into rubble, killed some 50,000 people, and inflicted devastating losses on Hamas’s military capabilities, manpower, intricate underground tunnel networks, and weapons arsenal.
At present, it is unclear whether Israeli troops will leave Gaza even if a cease-fire is reached. While Hamas may retain some semblance of control, its road to recovery and rebuilding as a functional member of the Axis of Resistance will be long and arduous.
Despite these catastrophic blows, the Axis maintains a degree of resilience. Iran and Iran-backed militias known as Popular Mobilization Forces (PMF) continue to wield substantial power in Iraq. During the HTS offensive in Syria, the PMF expressed willingness to enter Syria and fight in support of the Assad regime. Even though they did not follow through, the militias demonstrated their enduring military capability and continued ideological and political alignment with Iran. Furthermore, the U.S.-Iraq announcement in 2024 regarding the further withdrawal of American forces from Iraq over the next year offers Iran and its Iraqi affiliates a strategic opportunity to consolidate their influence and try to compensate for losses in Syria.
However, similar to the threat of a Sunni insurgency in Lebanon, HTS-led rule in Syria could inspire a Sunni revolt in Iraq. Many of the HTS high command were members of ISIS or Al-Qaeda in Iraq and possess intimate knowledge and connections in the region. A new Sunni revolt could undermine Shi’ite dominance and Iran’s influence.
Farthest from Israel is the one Axis member that appears to have thrived since 2023 – the Houthis of Yemen. Their continuous disruption of maritime traffic in the Red Sea and the seeming inability of a U.S.-backed naval coalition to effectively neutralize this threat highlight the group’s growing strength. Additionally, ongoing ballistic missile attacks on Israel, including successful strikes on central targets such as Tel Aviv, underscore the Houthis’ rapid progress in positioning themselves as Iran’s “New Hezbollah.”
The Houthis possess several advantages over Hezbollah that enhance their strategic value to Iran. First, the distance between Yemen and Israel limits Israel’s ability to effectively target the Houthis. Second, the Houthis’ tribal structure and the rugged, inhospitable terrain in Yemen make them inherently more elusive and difficult to neutralize.
Still, as 2025 begins, Iran’s Axis of Resistance no longer functions effectively as a tool for advancing Iran’s regional ambitions, nor as a key pillar of its deterrence strategy. Israel’s recent aerial strikes against Iran, which appear to have significantly degraded Iran’s air defense capabilities, have left the country more vulnerable than ever, and the Iranian economy also continues to falter. This represents a profound challenge to Iran’s strategic posture.
In this context, there is growing concern that a weakened and increasingly vulnerable Iran, governed by a survivalist regime, may see no alternative but to weaponize its decades-long nuclear program.
While the Axis of Resistance is now significantly weakened, its diminished state still presents considerable dangers for the United States’ position in the Middle East and the broader stability of the region. A fragile Iranian regime, desperate to survive, may become an even greater source of instability.
Arman Mahmoudian is a research fellow at the Global and National Security Institute (GNSI), and a lecturer at the University of South Florida (USF). His handle on X, formerly known as Twitter, is @MahmoudianArman
Iran’s ‘Axis of Resistance’ Weakened But Still Dangerous
By Arman Mahmoudian
Middle East & North Africa
Editor’s Note: Arman Mahmoudian is an expert on the so-called ‘Axis of Resistance’ – non-state militant groups that have been supported by Iran and share an anti-Israel and anti-U.S. ideology. He is a frequent contributor to Stimson on these topics and has written presciently about the dynamics leading up to Hamas’s Oct. 7 attack on Israel.
By Barbara Slavin, Distinguished Fellow, Middle East Perspectives
Iran enters 2025 with its large network of state and non-state allies – built up painstakingly over nearly half a century — severely damaged.
Iran has sponsored and funded this network running from Lebanon to Yemen, Gaza to Iraq, not only to project power but also as a deterrent against its primary adversaries, the United States and Israel. However, events beginning with Hamas’s devastating attacks on Israel on October 7, 2023, have boomeranged in spectacular fashion, decimating key figures and structures within the alliance.
The oldest member of the so-called Axis of Resistance and the cornerstone of Iran’s regional strategy was the Syrian regime of the Assad family. Syria was one of the first countries to recognize the Islamic Republic of Iran after the 1979 revolution, among Iran’s top suppliers during the 1980-88 Iran-Iraq War, and one of Iran’s very few friends in the Arab world. Iran returned the favor by mobilizing support for the Assad regime following the 2011 April Spring uprising and with Russian help, enabled the regime to keep control over much of the Syrian heartland. However, in December 2024, the regime collapsed after an 11-day offensive by Hay’at Tahrir al-Sham (HTS), a Turkish-backed Sunni Muslim militia from Idlib, which had remained in rebel hands. Billions of dollars in Iranian investment evaporated seemingly overnight and Iran lost its premier gateway to the Arab world.
It was through Syria in 1983 that Iran sent a division of its newly formed Islamic Revolutionary Guard Corps (IRGC) to Lebanon, laying the foundation for the creation of Hezbollah, the most potent non-state actor in the Axis of Resistance. For decades, Syria facilitated the transfer of weapons, resources, trainers, and troops from Iran to Lebanon, ensuring Hezbollah’s operational strength as it grew to dominate the Lebanese state and support Iran-backed militants from Iraq to Yemen.
The loss of Syria as a strategic ally is a severe blow to the Axis of Resistance. Without Syria as a land link, the Axis faces significant logistical and strategic challenges, threatening its cohesion and effectiveness.
The fall of the Assad regime also threatens Hezbollah’s position in Lebanon. With Syria under the influence of a Sunni militant group, there is the possibility of a Sunni insurgency against Hezbollah in Lebanon.
Hezbollah’s decision to open a second front against Israel after the October 27, 2023, Hamas attacks, instead of restraining Israeli actions in Gaza, led to a full-scale second Israel-Lebanon war. Hezbollah suffered catastrophic losses: its entire high command was eliminated, thousands of its troops were killed, and a significant portion of its arsenal was destroyed. For Iran, rebuilding Hezbollah is an urgent priority. However, it is unclear how Iran can accomplish this goal without Syria as a conduit.
The events of October 7, 2023, have also had a devastating impact on one of the least compatible members of the Axis, Hamas. The Sunni radical militants of Gaza have long been an inconvenient ally for Shi’ite Iran. During the Syrian civil war, for example, Hamas openly sided with Assad’s opponents, and its leaders have publicly criticized Shi’ite Islam, dismissing it as a “false branch” of Islam. Yet, Iran continued to support Hamas due to a shared perception of mutual threats from Israel and the United States.
In the past 15 months, however, Israel has eliminated Hamas’s military leadership, including Yahya Sinwar and Mohammed Deif, and assassinated its political leader Ismail Haniyeh in Tehran. Israel’s large-scale ground invasion of Gaza, coupled with a bombing blitz, has turned much of the enclave into rubble, killed some 50,000 people, and inflicted devastating losses on Hamas’s military capabilities, manpower, intricate underground tunnel networks, and weapons arsenal.
At present, it is unclear whether Israeli troops will leave Gaza even if a cease-fire is reached. While Hamas may retain some semblance of control, its road to recovery and rebuilding as a functional member of the Axis of Resistance will be long and arduous.
Despite these catastrophic blows, the Axis maintains a degree of resilience. Iran and Iran-backed militias known as Popular Mobilization Forces (PMF) continue to wield substantial power in Iraq. During the HTS offensive in Syria, the PMF expressed willingness to enter Syria and fight in support of the Assad regime. Even though they did not follow through, the militias demonstrated their enduring military capability and continued ideological and political alignment with Iran. Furthermore, the U.S.-Iraq announcement in 2024 regarding the further withdrawal of American forces from Iraq over the next year offers Iran and its Iraqi affiliates a strategic opportunity to consolidate their influence and try to compensate for losses in Syria.
However, similar to the threat of a Sunni insurgency in Lebanon, HTS-led rule in Syria could inspire a Sunni revolt in Iraq. Many of the HTS high command were members of ISIS or Al-Qaeda in Iraq and possess intimate knowledge and connections in the region. A new Sunni revolt could undermine Shi’ite dominance and Iran’s influence.
Farthest from Israel is the one Axis member that appears to have thrived since 2023 – the Houthis of Yemen. Their continuous disruption of maritime traffic in the Red Sea and the seeming inability of a U.S.-backed naval coalition to effectively neutralize this threat highlight the group’s growing strength. Additionally, ongoing ballistic missile attacks on Israel, including successful strikes on central targets such as Tel Aviv, underscore the Houthis’ rapid progress in positioning themselves as Iran’s “New Hezbollah.”
The Houthis possess several advantages over Hezbollah that enhance their strategic value to Iran. First, the distance between Yemen and Israel limits Israel’s ability to effectively target the Houthis. Second, the Houthis’ tribal structure and the rugged, inhospitable terrain in Yemen make them inherently more elusive and difficult to neutralize.
Still, as 2025 begins, Iran’s Axis of Resistance no longer functions effectively as a tool for advancing Iran’s regional ambitions, nor as a key pillar of its deterrence strategy. Israel’s recent aerial strikes against Iran, which appear to have significantly degraded Iran’s air defense capabilities, have left the country more vulnerable than ever, and the Iranian economy also continues to falter. This represents a profound challenge to Iran’s strategic posture.
In this context, there is growing concern that a weakened and increasingly vulnerable Iran, governed by a survivalist regime, may see no alternative but to weaponize its decades-long nuclear program.
While the Axis of Resistance is now significantly weakened, its diminished state still presents considerable dangers for the United States’ position in the Middle East and the broader stability of the region. A fragile Iranian regime, desperate to survive, may become an even greater source of instability.
Arman Mahmoudian is a research fellow at the Global and National Security Institute (GNSI), and a lecturer at the University of South Florida (USF). His handle on X, formerly known as Twitter, is @MahmoudianArman
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