On 17 September 1980 Sadam Hussein announced that he was ending the treaty with Iran that had been agreed in 1975, five days later the Iraqi armed forces had started a massive offensive and by the end of October 1980 Khorramshar, the largest port in Iran had fallen to Iraqi forces, who were now threatening the Iranian oil capital of Abadan and the regional capital of Khuzestan.
To on lookers it seemed that the more technically advanced Iraqis would win the war easily and quickly, but this image quickly faded as it became clear that the Iraqi forces were badly lead and lacked spirit, while the Iranians were determined to put up a fierce fight. Despite heavy Iraqi shelling both Abadan and Khorramshar held and the Iranians launched a counter attack during the spring and summer of 1981.
Official Iraqi sources blamed this reversal on the lines of communication being too long and a lack of experience among the Iraqi troops and reservists. Another excuse put forward was that the largely mechanized Iraqis were at a disadvantage when the Iranians attacked with infantry under the cover of darkness.
The war continued to drag on becoming increasing bloody as mass attacks by Iranian infantry were drive back at high cost to both sides.Iran held the advantage thanks to a massive offensive in May 1982 when they drove Iraqi forces back to the border. Another series of offensives in 1984 allowed the Iranians to cross the border in Kurdistan and move towards the Tigris river. Finally the Iranians seized Majnoon island in southern Iraq centre for oil production in this marshy region which was notoriously difficult to move troops into. It was during this phase of the war that the Iraqis made use of poison gas to repel Iranian attacks, both mustard gas and the more modern nerve gas were used demonstrating the Iraqi capability to manufacture and deploy such weapons of mass destruction.
In 1986 Iranian troops crossed the marshes at the mouth of the Shatt al-Arab and captured the Faw peninsula. 1987 saw a massive Iranian assault against Iraqis second largest city Basra which was almost successful. The offensive forced much of the city's population to flee and heavy artillery bombardment did the city considerable damage. Despite this the Iraqis held on and the war settled into this pattern of Iranian offensive held off by Iraqi defence. Shiism stresses the importance of becoming a martyr and many thousands of young Iranians volunteered and died in this war of attrition in many ways similar to the First World War. Iranian volunteers would hurl themselves forward in a suicidal onslaught to clear the way for more regular Iranian troops who would then face the Iraqi trenches and dug in defences. The war also saw the use of bombers and missiles to attack cities, making this a 'Total War'. Iraq first bombed Iranian cities in 1984 starting with Dizful and moving on to Tehran and other cities, although neither side had enough bombers to do much damage. 1987 saw the first use of missiles against civilian populations with Iraqi SCUD missiles modified to reach Tehran being used by the Iraqis. Many fled the city and some put the number of refugees at 4 million, half the city's population. Iran retaliated by using missiles against Baghdad.
The spring of 1988 saw the last major offensive, Iranian troops broke through in Kurdistan and nearly captured the hydro electric dam at Dukan, capturing 400 square miles of Iraq. Iraqi was on the verge of defeat and backed into a corner they used poison gas to stop the Iranians. In march 1988 a war crime was committed when the Kurdish village of Halabjah under Iranian occupation was hit by gas killing at least 100 civilians, Iran claimed 2000 had died and a UN report later confirmed the use of poison gas on a civilian target by the Iraqis. The use of chemical weapons allowed the Iraqi's to halt the attack without using up reinforcements who were sent instead to a surprise offensive in the south helping Iraq to recapture the Faw peninsula and drive the Iranians back across the Shatt. This was the turning point and the Iranian army started to be rolled back with the Iraqis regaining nearly all the land they had lost in the war. Things went from bad to worse for the Iranians as an Iraqi armed rebel army made up of exiled Iranians attacked via Kurdistan, the National Liberation Army or NLA.
Iraqi had at last turned the tide now portraying itself as a modern secular state fighting against a fanatical religious enemy. Relations with other Arab states started to normalize and diplomatic relations and possibly arms shipments, resumed with America. Certainly the Americans allowed European arms dealers access to Iraq such as the French whereas Iran still had an arms embargo. Europe supplied the arms and the moderate Arab states fearful of Islamic fundamentalism supplied the money for Iraqis war effort. Finally Iran was becoming war weary, fighting the war mostly on Iraqi soil mean long supply lines across mountainous terrain. The Iraqi victories were the last straw for Iran and on 18 July 1988 Tehran announced that it would accept the UN proposed ceasefire which took effect on 20 August 1988.
Casualty figures are difficult to verify but it is estimated that Iranian suffered around 500,000 dead between 1980 and 1988 while Iraq suffered about 150,000 dead, with a further 500,000 wounded and 70,000 captured. Iran could afford the higher causalities having a population of around 50 million compared to Iraq's 18 million. Iraq may have won but it gained none of the spoils as the Shatt al-Arab was now clogged and unusable and Iraq had built up $80 billion of foreign debt which the Arab states such as Kuwait refused to write off. The invasion of Kuwait (leading to the Gulf War) was seen by the Iraqis as the only way to cancel this debt with long term and bloody consequences for the Iraqi people who had already suffered years of fighting. See also the 'Tanker War'