The Iran-Iraq War (or First Persian Gulf War) was a border war between Iran and Iraq which lasted from September 22, 1980 until August 20, 1988. This war was commonly known as the Persian Gulf War until the Iraq-Kuwait Conflict (1990-91), which became known as the Second Gulf War and later simply the Gulf War.
The conflict was occasioned by Iraqi President Saddam Hussein's desire for full control of the Shatt al-Arab waterway at the head of the Persian Gulf, an important channel for the oil exports of both countries. The United States armed and encouraged Hussein to attack Iran over this disputed waterway as a possible way of undermining the Iranian Revolution of 1979 which had eliminated U.S. influence in Iran. In 1975, Secretary of State Henry Kissinger had sanctioned the Shah of Iran to attack Iraq over the waterway, which was then under Iraqi control. Iraq and other Arab countries also feared the possible spread of Iran's brand of Islamic militancy following the February 1979 revolution against the Shah. Iraq also had designs on the Iranian province of Khuzestan which has an Arab majority.
Another factor that precipitated the Iran-Iraq conflict was the ambition of the leaders of each country. Ayatollah Khomeini had designs on spreading his brand of Islamic Fundamentalism throughout the middle east. These efforts were minimal, however, as the Islamic Revolution had only recently seized control of Iran. Hussein had also recently come to power and was interested in elevating Iraq to a regional superpower. A successful invasion of western Iran would make Iraq the sole dominating force in the Gulf region and its lucrative oil trade. Such lofty ambitions were not that farfetched. Severe officer purges and spare part shortages for Iran's American made equipment had crippled Iran's once mighty military. To top it off, Iran had minimal defenses in the Shatt al Arab area. On September 22, 1980, Iraq seized the opportunity and invaded, using the Iran-backed assassination attempt aimed at then-Foreign Minister Tariq Aziz as a pretext for the attack.
Iraq enjoyed substantial diplomatic support and military supplies from the Soviet Union, and the financial backing of other Arab states (notably oil-rich Kuwait and Saudi Arabia). In addition, the United States "tilted" toward Iraq, supplying it with weapons and economic aid. For a period starting in 1985, the United States sold weapons to Iran in addition to Iraq. This sparked the 1986-1988 Iran-Contra Affair in Washington.
The war was characterized by extreme brutality, including the use of chemical weapons, including tabun, by Iraq. Very little pressure was brought upon Iraq by the world community to curb such attacks or to condemn its earlier initiation of hostilities. The tactics used in the war resembled those of World War I with costly human wave attacks commonly used by both sides.
In June 1982 a successful Iranian counter-offensive recovered the areas lost to Iraq in the war's early stages: Iraq offered a cessation of hostilities as outright Iranian victory appeared a possibility, but Iran's insistence from July on pursuing the destruction of the Iraqi regime prolonged the conflict for another six years.
Continued hostilities despite the intervention of western naval forces to protect the sealanes of the Gulf led to the death of 37 seamen in an Iraq missile attack (May 17, 1987) on the U.S. frigate Stark and the shooting down by the U.S. cruiser Vincennes (July 3, 1988) of an Iranian airliner (apparently mistaken for an approaching military aircraft) with the loss of all 290 passengers and crew.
The war was disastrous for both countries, stalling economic development and disrupting oil exports, and costing an estimated million lives. Iraq was left with serious debts to its former Arab backers, including $14 billion loaned by Kuwait, a debt which contributed to Hussein's 1990 decision to invade Kuwait.
The end of the war left the borders unchanged. Two years later, as war with the western powers loomed, Hussein recognised Iranian rights over the eastern half of the Shatt al-Arab, a reversion to the status quo which he had repudiated a decade earlier.
The war would be extremely costly, one of the deadliest wars since the Second World War in terms of casualties. It is surpassed only by conflicts such as the Vietnam War, Korean War and the war in the Democratic Republic of the Congo in Africa of the late 20th and early 21st centuries. While figures vary wildly, roughly a million people are estimated to have died.
During this war, the personnel of the Iraqi Army increased from 242,250 to 1,200,000 troops.
See also: Middle East conflict -- History