As West Asia remains mired in conflict, it is worth examining how the United States-led global war on terror inadvertently emboldened Iran, elevating it to a regional power that is now capable of confronting the U.S. in the ongoing conflict.

Prior to 2001, Iran faced strategic containment from two hostile regimes: the Taliban in Afghanistan and Saddam Hussein’s Iraq. U.S. invasions toppled both governments, eliminating Iran’s most dangerous neighbours. The new governments in both countries proved friendlier to Tehran. In Iraq, the fall of the Sunni regime led to a Shia-led government with deep ties to Iran, transforming an enemy into a strategic partner. According to analysts, Iran had surpassed the U.S. as the most influential power in Iraq, significantly improving its strategic position.

Sectarianism was the fuel

The invasions of Afghanistan and Iraq created a chaotic environment in the region that fuelled sectarian conflicts centred on the Shia-Sunni divide. These developments provided fertile ground for the emergence of terrorist groups such as al-Qaeda in Iraq, which later evolved into the Islamic State of Iraq and Syria (ISIS). Regional powers took sides — Iran bolstered Shia militias in Iraq, while Saudi Arabia supported Sunni extremists. This sub-conventional proxy warfare entrenched Iran as a regional power broker, contrary to the overarching U.S. objective of isolating Iran.

ISIS, being ideologically anti-Shia, posed an unprecedented threat to Iran. This pushed Iran to become a central actor in the anti-ISIS coalition, deploying military advisers and mobilising allies across the region.

Iran consolidated its influence by becoming a key counter-terrorism player, exploiting power vacuums and using the crisis to strengthen its diplomatic position. Though the emergence of a shared enemy opened a narrow window for dialogue with the U.S., no synchronisation materialised, as President George W. Bush had famously labelled Iran part of the ‘Axis of Evil’ in his 2002 State of the Union address, alongside Iraq and North Korea, citing their pursuit of weapons of mass destruction and support for terrorism.

The role of the ‘Axis of Resistance’

However, from Iran’s point of view, what mattered was the “Axis of Resistance” (the Axis) — a political, military, and social network linking Iran, Iraq, Syria, Lebanon, and Palestine. It was designed as a “ring of fire” around Israel, serving as a form of forward defence for Iran. In addition, Iran gained several buffer zones in Iraq, Lebanon, Syria, and Yemen through key Axis members such as Hezbollah, Hamas, the Houthis, and Shia militias in Iraq. The Axis contributed to the emergence of the “Shia Crescent”, an arc of Iranian influence extending through Iraq, Syria, and Lebanon.

Iran gained international legitimacy for its military activities in Iraq and Syria. Groups such as Hezbollah became battle-hardened and politically entrenched. The Houthis in Yemen graduated from a local insurgent movement into a political insurgent group. In terms of military capabilities, Iran’s primary focus was on the Islamic Revolutionary Guard Corps (IRGC), which controls the country’s strategic assets and specialises in sub-conventional warfare, including the control of proxies. By comparison, Iran’s conventional military received far less attention.

The U.S. withdrawal from Iraq and the Arab Spring in 2011 created vacuums that Iran was uniquely positioned to fill. Iran invested significantly in the Axis to gain an asymmetric advantage over the U.S. and Israel, as matching them on conventional military metrics was a difficult proposition for Tehran.

The “Forever Wars” in West Asia drained American resources and attention, allowing Iran to expand its influence unimpeded while reinforcing its hardline posture. The rise of ISIS paradoxically benefited Iran, which became one of the first and most critical military supporters of the Iraqi government in its fight against the group. Iran deployed its elite Quds Force to coordinate Baghdad’s defence, cementing its influence over Iraq’s security apparatus. In Syria, defending the Assad regime protected Iran’s only major state ally and helped consolidate its supply routes to Hezbollah in Lebanon.

The transformation of Iran

The global war on terror fundamentally transformed Iran from a contained state into a dominant regional power. By removing hostile regimes, creating power vacuums, and unintentionally strengthening Iran’s alliance network, U.S. actions produced outcomes diametrically opposed to their stated objectives.

The global war on terror enabled Tehran to project power in Afghanistan, Lebanon, Syria, and Yemen. As a result, Iran’s role as a pivotal broker was cemented, with lasting consequences for West Asian geopolitics.

Having benefited from these developments, Iran increasingly invested in the Axis while rallying domestic support around nationalism rather than religion. Iran’s current resilience against the U.S.-Israeli offensive in West Asia could be viewed as a manifestation of the strategic advantages flowing from the global war on terror.

Shashank Ranjan is an Indian Army veteran (Colonel), currently teaching at the O.P. Jindal Global University, Sonepat, Haryana