On January 8, 1987, Iran launched its long-anticipated offensive on Basra, which became the largest and bloodiest battle of the war. Some 600,000 Iranian soldiers took part and faced 400,000 Iraqi defenders. The seven-week offensive, which lasted until late February 1987, saw the Iranians launching successive assaults that succeeded in breaching four of the five Iraqi “dynamic defense” lines, including the modified barriers Fish Lake and Jasim River, and to come to within twelve kilometers of Basra, before being stopped. Iranian casualties were considerable– some 65,000 were killed; 20,000 Iraqi soldiers also perished.
The failure to capture Basra had a powerful demoralizing effect on Iran: in the aftermath, much fewer civilians volunteered to join the Revolutionary Guards and Basij, the general population became war-weary and felt the war was unwinnable, and even the Iranian leadership stopped plans for further major operations or “final offensives”.
(Excerpts taken from Iran-Iraq War – Wars of the 20th Century – Volume 4)
Background In 1937, the now independent monarchies of Iraq and Iran signed an agreement that stipulated that their common border on the Shatt al-Arab was located at the low water mark on the eastern (i.e. Iranian) side all across the river’s length, except in the cities of Khoramshahr and Abadan, where the border was located at the river’s mid-point. In 1958, the Iraqi monarchy was overthrown in a military coup. Iraq then formed a republic and the new government made territorial claims to the western section of the Iranian border province of Khuzestan, which had a large population of ethnic Arabs.
In Iraq, Arabs comprise some 70% of the population, while in Iran, Persians make up perhaps 65% of the population (an estimate since Iran’s population censuses do not indicate ethnicity). Iran’s demographics also include many non-Persian ethnicities: Azeris, Kurds, Arabs, Baluchs, and others, while Iraq’s significant minority group comprises the Kurds, who make up 20% of the population. In both countries, ethnic minorities have pushed for greater political autonomy, generating unrest and a potential weakness in each government of one country that has been exploited by the other country.
The source of sectarian tension in Iran-Iraq relations stemmed from the Sunni-Shiite dichotomy. Both countries had Islam as their primary religion, with Muslims constituting upwards of 95% of their total populations. In Iran, Shiites made up 90% of all Muslims (Sunnis at 9%) and held political power, while in Iraq, Shiites also held a majority (66% of all Muslims), but the minority Sunnis (33%) led by Saddam and his Baath Party held absolute power.
In the 1960s, Iran, which was still ruled by a monarchy, embarked on a large military buildup, expanding the size and strength of its armed forces. Then in 1969, Iran ended its recognition of the 1937 border agreement with Iraq, declaring that the two countries’ border at the Shatt al-Arab was at the river’s mid-point. The presence of the now powerful Iranian Navy on the Shatt al-Arab deterred Iraq from taking action, and tensions rose.
Also by the early 1970s, the autonomy-seeking Iraqi Kurds were holding talks with the Iraqi government after a decade-long war (the First Iraqi-Kurdish War, separate article); negotiations collapsed and fighting broke out in April 1974, with the Iraqi Kurds being supported militarily by Iran. In turn, Iraq incited Iran’s ethnic minorities to revolt, particularly the Arabs in Khuzestan, Iranian Kurds, and Baluchs. Direct fighting between Iranian and Iraqi forces also broke out in 1974-1975, with the Iranians prevailing. Hostilities ended when the two countries signed the Algiers Accord in March 1975, where Iraq yielded to Iran’s demand that the midpoint of the Shatt al-Arab was the common border; in exchange, Iran ended its support to the Iraqi Kurds.
Iraq was displeased with the Shatt concessions and to combat Iran’s growing regional military power, embarked on its own large-scale weapons buildup (using its oil revenues) during the second half of the 1970s. Relations between the two countries remained stable, however, and even enjoyed a period of rapprochement. As a result of Iran’s assistance in helping to foil a plot to overthrow the Iraqi government, Saddam expelled Ayatollah Khomeini, who was living as an exile in Iraq and from where the Iranian cleric was inciting Iranians to overthrow the Iranian government.
However, Iranian-Iraqi relations turned for the worse towards the end of 1979 when Ayatollah Khomeini was proclaimed as Iran’s absolute ruler. Each of the two rival countries resumed secessionist support for the various ethnic groups in the other country. Iran’s transition to a full Islamic State was opposed by the various Iranian ethnic minorities, leading to revolts by Kurds, Arabs, and Baluchs. The Iranian government easily crushed these uprisings, except in Kurdistan, where Iraqi military support allowed the Kurds to fend off Iranian government forces until late 1981 before also being put down.
Ayatollah Khomeini, in line with his aim of spreading Islamic revolutions across the Middle East, called on Iraq’s Shiite majority to overthrow Saddam and his “un-Islamic” government, and establish an Islamic State. In April 1980, a spate of violence attributed to the Islamic Dawa Party, an Iran-supported militant group, broke out in Iraq, where many Baath Party officers were killed and other high-ranking government officials barely escaped assassination attempts. In response, the Iraqi government unleashed repressive measures against radical Shiites, including deporting thousands who were thought to be ethnic Persians, as well as executing Grand Ayatollah Mohammad Baqir al-Sadr, which drew widespread condemnation from several Muslim countries as the religious cleric was highly regarded in the wider Islamic community.
Throughout the summer of 1980, many border clashes broke out between forces of the two countries, increasing in intensity and frequency by September of that year. As to the official start of the war, the two sides have different interpretations. The Iraqis cite September 4, 1980, when the Iranian Army carried out an artillery bombardment of Iraqi border towns, prompting Saddam two weeks later to unilaterally repeal the 1975 Algiers Accord and declare that the whole Shatt al-Arab lay within the territorial limits of Iraq.
September 22, 1980, however, is generally accepted as the start of the war, when Iraqi forces launched a full-scale air and ground offensive into Iran. Saddam believed that his forces were capable of achieving a quick victory, his confidence borne by the following factors, all resulting from the Iranian Revolution. First, as previously mentioned, Iran faced regional insurgencies from its ethnic minorities that opposed Iran’s adoption of Islamic fundamentalism. Second, Iran further was wracked by violence and unrest when secularist elements of the revolution (liberal democrats, communists, merchants and landowners, etc.) opposed the Islamist hardliners’ rise to power. The Islamic state subsequently marginalized these groups and suppressed all forms of dissent. Third, the revolution seriously weakened the powerful Iranian Armed Forces, as military elements, particularly high-ranking officers, who remained loyal to the Shah, was purged and repressive measures were undertaken to curb the military. Fourth, Iran’s newly established Islamic government, because it rejected both western democracy and communist ideology, became isolated internationally, even among Arab and Muslim countries.