The Iranian intervention in Iraq has its roots in the post-2003 invasion of Iraq by the United States and allies when the infrastructure of the Iraqi armed forces, as well as intelligence, were disbanded in a process called "de-Ba'athification" which allowed militias with close ties to Tehran to join the newly reconstituted army.
The intervention reached its peak following the advance of the Islamic State into northern Iraq in mid-2014, Iran began to provide military aid to counter the militant advance. Iran provided technical advisers to the Iraqi government and weapons to the Kurdish Peshmerga. Several sources, among them Reuters, believe that since mid-June 2014, Iranian combat troops are in Iraq, which Iran denies.
The Iraqi Shia militias Kata'ib Hezbollah ("Hezbollah Brigades") and Asa'ib Ahl al-Haq ("League of the Righteous"), funded and trained by Iran, fought alongside the Iraqi Army and Peshmerga in retaking territory from ISIL.
Background
US invasion of Iraq
After the 2003 invasion of Iraq by the United States and its allies, The Coalition Provisional Authority disbanded the Iraqi military, security, and intelligence infrastructure of President Saddam Hussein and began a process of "de-Ba'athification". This move became an object of controversy, cited by some critics as the biggest American mistake made in the immediate aftermath of the fall of Saddam Hussein and as one of the main causes of the rise of the Islamic State.
The Badr organisation, which fought alongside Iran in the Iran-Iraq war, was seen as a U.S. asset in the fight against Ba'athist partisans because of their opposition to Saddam Hussein. Shortly after the fall of Baghdad, Badr forces and other militias with close ties to Tehran reportedly joined the newly reconstituted army, police, and Interior Ministry in significant numbers. The Interior Ministry was controlled by SCIRI, and many Badr members became part of the Interior Ministry-run Wolf Brigade. The Iraqi Interior Minister, Bayan Jabr, was a former leader of the Badr Brigade militia.
The Islamic Supreme Council of Iraq and various other parties with military wings, all with close ties with Tehran, had pioneering role in forming the governments with close ties to Tehran.
According to the U.S. military and U.S. State Department, the Iraqi Shia militia Kata'ib Hezbollah ("Hezbollah Brigades"), which has existed since 2003, has received funding, training, logistics, guidance, and material support from the Iranian Islamic Revolutionary Guard Corps's Quds Force. Iran denies these claims.
Asa'ib Ahl al-Haq ("League of the Righteous"), another Iraqi Shia militia, formed in 2006, was assumed by Iraqi officials to have been receiving $2 million a month from Iran even before 2014, and assumed by The Guardian to be under the patronage of Qasem Soleimani.
Opposing the intervention
In 2019, protests broke out in Iraq demanding the end of corruption, nepotism, unemployment, and political sectarianism while also calling for an end to Iranian intervention in Iraqi affairs. The Abdul-Mehdi government, backed by Iranian-backed militias used live bullets, marksmen, hot water, hot pepper gas, and tear gas against protesters, leading to many deaths and injuries.
The protests resulted in the resignation of Prime Minister Abdul-Mahdi and his government, and the appointment of Mustafa Al-Kadhimi. A new election law was also passed by the Council of Representatives.
The 2021 parliamentary election resulted in Pro-Iran parties losing seats in the newly elected Iraqi parliament and in turn led to 2021 Baghdad clashes.
In November 2021, Al-Kadhimi survived an assassination attempt via an explosive drone, two drones were shot down by the army while the last one targeted his residence in the heavily fortified Green Zone district of Baghdad.
According to experts, the assassination attempt came as a response to pro-Iran parties losing seats in the 2021 Iraqi parliamentary election.
Intervention
Strategy and tactics
Tehran's strategic objectives in its intervention in Iraq include keeping the Shia-led government in power and stabilising its border.