The History of U.S.-Iranian Irregular Warfare
Editor’s Note: this article is being republished with the permission of the Irregular Warfare Initiative as part of a republishing arrangement between IWI and SWJ. The original article was published on 26 August 2025 and is available here.
The relationship between the United States and Iran is far more intricate than a conventional bilateral conflict. Dubbed the “twilight war,” U.S.-Iranian relations is replete with examples of Irregular Warfare (IW), including events of the recent past like the U.S.-Russia-Iran proxy war in Syria, the Yemeni proxy war between Saudi Arabia and Iran, Iranian support to Hamas for October 7th, Iran’s assassination plot of the Saudi ambassador to the United States, and the U.S. targeting of Iranian General Qassem Soleimani in 2020. For the United States, leveraging Irregular Warfare helps implement an approach meant to “restor[e] maximum pressure on the government of the Islamic Republic of Iran (IRI), denying Iran all paths to a nuclear weapon, and countering Iran’s malign influence abroad”—such as Iran’s own IW campaign in the Middle East. A historical review of U.S.-Iran relations and military actions shows this trend is not new, but instead demonstrates its continued role in shaping today’s strategic environment.
From Shah to Ayatollah: The Iranian Revolution and Changes in US-Iran Relations
In 1949, the United States established the Voice of America (VOA), which began broadcasting in Iran that year, promoting “liberal developmentalism” centered on modernization, improved technical capacity, political pluralism, and American music in order to contain Soviet influence and promote Westernization in Iran. In 1953, U.S. and British intelligence agencies supported a coup to overthrow democratically elected Iranian Prime Minister Mohammed Mossadegh. The CIA supported this subversion to shield the British-owned Anglo-Persian Oil Company and mitigate wider economic risks after Mossadegh nationalized Iranian oil and resisted Western interests.
The coup restored the Western-friendly monarchy under Shah Mohammad Reza Pahlavi. Deeply unpopular among Iranians, the Shah relied on U.S. support to maintain power. In 1954, the Shah signed the Consortium Agreement that granted U.S., British, and French oil companies 40 percent ownership of Iran’s oil industry for 25 years. From 1957, the United States provided Iran support for nuclear, military, economic, and governance programs.
Despite U.S. foreign assistance and aggressive modernization efforts led by Mohammad Reza Shah Pahlavi (known as the White Revolution), anti-Western, anti-government, and anti-modern movements influenced by Marxist idealism and Shia Islamic traditions began taking root in the 1960s among Iranian intellectuals and a disgruntled middle class. This popular front culminated into the Islamic Revolution in 1979, spreading protests and riots within Iran amid worsening socio-economic conditions. The revolution deposed the Pahlavi monarchy in February 1979 and emplaced the Supreme Leader Ruhollah Khomeini as the theocratic head of the new government by October.
In November 1979, a group called the Muslim Student Followers of the Imam’s Line seized 66 American hostages at the U.S. embassy in Tehran. They held 52 captives for 444 days and demanded the extradition of the Shah, who had fled during the revolution. In response, the US severed diplomatic ties with Tehran, imposed sanctions on Iranian oil imports, and froze Iranian assets. In April 1980, President Jimmy Carter authorized Operation Eagle Claw, a doomed Special Operations Forces (SOF) mission to rescue the hostages that resulted in eight U.S. servicemembers killed. In January 1981, the hostages were released under the Algiers Accords, whereby the United States pledged non-interference in Iran’s politics.
The Iran-Iraq War and U.S.-Iranian Shadow Warfare during the 1980s and 1990s
Employing an IW approach, the United States provided proxy-like support to Iraq during the Iran-Iraq War, supplying Iraq with economic aid, training, and technology. Iran responded in kind. In 1983, Islamic Jihad, one of the precursor organizations that later formed Hezbollah, drove trucks laden with explosives into a Marine barracks housing American and French military personnel in Lebanon, killing 241 U.S servicemembers. Iran’s Revolutionary Guard Corps (IRGC) played a central role in creating, training, and funding Hezbollah in the early 1980s, transforming the group into a fully operational proxy militia that advanced Tehran’s strategic objectives and forced the United States to withdraw later that year.
After the Persian Gulf War ended in 1991 with the United States’ conventional victory over Iraq, the United States turned to non-military tools to contain Iran through sanctions and diplomacy. By May 1993, the Clinton administration introduced the Dual Containment Policy to isolate both Iraq and Iran, also imposing the Iran-Iraq Arms Nonproliferation Act and the Iran and Libya Sanctions Act in an attempt to prevent Iran from gaining asymmetric capabilities or projecting force beyond its borders.
The Global War on Terror: Iranian Asymmetric Tactics and U.S. Responses
After the September 11th attacks, the United States and Iran initially cooperated against their common enemies. Iran, a Shia-majority state, opposed Sunni extremist groups like the Taliban, al Qaeda, and ISIS. However, this cooperation was short-lived and ended in 2002 when President George W. Bush labeled Iran part of the “axis of evil” alongside Iraq and North Korea. Iran halted secret cooperation aimed at countering al Qaeda and the Taliban, and became the largest supporter of Shia militias fighting against U.S. forces in Iraq. To counter Iran’s influence, the United States passed the Iran Freedom Support Act in 2006 to fund Iranian civil society and promote democracy, indirectly pushing back against the regime in Tehran.
In 2010, the Stuxnet computer worm, widely attributed to the United States and Israel, destroyed 1,000 nuclear centrifuges in Iran. The following year, U.S. officials arrested two Iranians conspiring to assassinate the Saudi Ambassador to the United States in an attack allegedly directed by IRGC Qods Force officers.
Mitigating Iranian Nuclear Non-Proliferation and Escalating U.S.-Iranian Irregular Warfare
In 2015, Iran, the five permanent members of the UN Security Council, and Germany signed the JCPOA, offering sanctions relief to Iran in exchange for constraining its nuclear program. In 2018, the US unilaterally withdrew from the JCPOA, citing its temporary nature and lack of control over Iran’s ballistic missile program. The United States also reinstated sanctions and pressured Iraq to reduce energy imports from Iran.
In 2019, the United States designated the IRGC as a foreign terrorist organization, a first for a state military entity. U.S. officials attributed attacks on oil tankers in the Strait of Hormuz to Iran, and for the first time, Iran-backed Houthi rebels claimed responsibility for drone attacks on Saudi Aramco oil facilities, escalating Iran’s use of proxy forces against the United States and its partners.
In January 2020, a U.S. drone strike killed Major General Qassem Soleimani, commander of the Qods Force whom American officials claimed was planning attacks on American targets and framed the strike as a preemptive deterrence strategy. Iran retaliated by attacking U.S. bases in Iraq and then mistakenly shot down a Ukrainian passenger plane, killing 176 onboard.
In November of 2020, Iranian nuclear scientist Mohsen Fakhrizadeh was assassinated, likely by Israel, with Iran suspecting U.S. direct or indirect involvement. Iran responded by boosting uranium enrichment to 20 percent and threatening to expel International Atomic Energy Agency inspectors. In 2021, the United States and Iran revived JCPOA talks in Vienna, but an explosion at Natanz nuclear facility compelled Iran to enrich uranium to 60 percent. In June 2021, Ebrahim Raisi, a US-sanctioned judiciary chief notorious for signing thousands of death warrants after the Islamic Revolution and nicknamed “the hanging judge,” won Iran’s presidential election. The US government imposed sanctions on Raisi for his role in approving the post-revolution executions.
In 2022, the United States, Bahrain, Egypt, Israel, Morocco, and the UAE convened at the Negev Forum. While there was a nonmilitary agenda, secret military meetings with Israel and Arab states built a coalition to defend against Iranian drones and missiles. These efforts sought to build a united front against Iran’s asymmetric tactics and avoid direct confrontation. In 2022, protests erupted in Iran and denounced the Islamic Republic after the regime killed Mahsa Amini for wearing improper hijab. The regime arrested 12,500 people and killed over 200 in quelling the riots. The United States increased sanctions on Iran and announced an impasse on nuclear talks.
In 2023, the United States granted sanctions relief and unfroze Iranian assets worth $6 billion in exchange for the release of five Iranian-Americans detained in Iran. Due to Iran’s complicity in the October 7th, 2023 attack in Israel, the United States and Qatar instead prevented Iran from receiving the assets, effectively terminating the agreement. Iran’s support for the Russian invasion of Ukraine, particularly providing drones to Russia, further deteriorated diplomatic relations and broadened the scope of U.S.-Iranian competition across conflicts.
An Israeli group Western analysts dubbed “Predatory Sparrow” claimed responsibility for large-scale cyberattacks against Iran that disrupted fuel pumps in December 2023 and internet access in May 2024. While attribution remains inconclusive, these incidents represent disruptive cyberattacks, often linked to state-sponsored actors seeking to undermine adversaries. Retaliatory Iranian cyber-attacks emerged and persist today.
Historical Lessons from the Twilight War
This history between the United States and Iran suggests that even the most creative and technological strategies cannot substitute for long-term strategic discipline. IW offers powerful tools for disruption, deterrence, and pressure—but these instruments require integration with diplomacy, allied coordination, and narrative control. U.S. policy adjustments that fluctuate between a grand strategy of engagement, isolation, or maximum pressure dilute the effectiveness of a long-term campaign against Iran. Vision and patience are irreplaceable for long-term struggles among states and non-state actors alike.
Synchronization across all levers of government power is integral to effective IW and strategic impact. Blowback from irregular activities can undermine alliances, embolden adversaries, and damage reputational capital. Without legislative approval, the Iran-Contra scandal of the 1980s undermined U.S. credibility and created substantial political blowback. The 1953 coup that restored the Pahlavi Shah remains a grievance in Iranian political memory, fueling decades of anti-Americanism.
Although the cyber domain gains pertinence in modern warfare, strategists must holistically evaluate its disadvantages against its benefits. Cyber operations such as Stuxnet and the recent Predatory Sparrow attacks illustrate how non-kinetic tools can achieve outsized psychological and material effects without triggering escalation thresholds. Cyber tools are particularly attractive because of their deniability, scalability, and disruptive capability, but Stuxnet’s legacy includes shifting international norms for open cyber warfare and unrestrained offensive cyber operations.
Stuxnet also normalized covert cyber-attacks as permissible in the international system and prompted the proliferation of asymmetric threats below the threshold of conventional warfare. Without clear signaling and international buy-in, this trend could remain unchecked in perpetuity. However, the emerging integration of space, cyber, and SOF—referred to as the space-cyber-SOF triad—presents an opportunity to deliberately synchronize multiple domains for strategic effect.
Unprecedented Conventional Strikes and the Precedent for Irregular Warfare
Following a series of unprecedented strikes in 2025—first by Israel in April and then by Israel and the United States in June—on Iranian military and nuclear infrastructure, Iran responded with a multifaceted counteroffensive. Iran launched ballistic missile and drone attacks against Israeli and U.S. assets, while maintaining pressure through its regional proxies. The full extent of Iran’s retaliation strategy may materialize over months or years and could incorporate its constellation of non-state actors. Despite being weakened, Iran and its proxies demonstrate impressive coordination, speed of response, and technological maturity—many now employ precision-guided munitions, drones with advanced targeting, information warfare, and cyberattacks.
Iran will not likely temper its antagonistic proxy warfare. The impressive B-2 bombings have limitations in a broader strategy of containing Iranian nuclear weapons or degrading Iran’s aggression, especially as the battle damage assessment remains inconclusive. U.S. and Israeli military strikes in 2025 may only reinforce Iran’s perception that conventional deterrence alone is insufficient to ensure regime survival, thus incentivizing investment in irregular capabilities. Furthermore, Tehran will likely continue its partnerships with other U.S. adversaries—such as Russia, China, and North Korea—by offering proxy support, arms transfers, or coordinated influence to garner mutually aligned support and avoid isolation.
The United States still faces an adaptive and defiant Iranian regime. Episodic strikes and sanctions must shift toward a resilient strategy that disrupts Iran’s capacity for unconventional warfare. Future success against Iran hinges upon dismantling its proxy networks, charting a coherent foreign policy, maintaining international legitimacy, and reinforcing a regional order resistant to Iranian hybrid warfare. History and current events suggest that IW—for the US, Iran, and their partners—will remain central to Middle Eastern security dynamics until or unless one side prevails in the twilight war.
The views expressed are those of the author(s) and do not reflect the official position of the Irregular Warfare Initiative, Princeton University’s Empirical Studies of Conflict Project, the Modern War Institute at West Point, or the United States Government.
