Saddam Hussein darkest period was during the Iran-Iraq war in 1980–88. A protracted military conflict, It officially began on Sept. 22, 1980, with an Iraqi land and air invasion of western Iran, although Saddam maintained that Iran had been engaging in artillery attacks on Iraqi towns since Sept. 4.
Saddam’s reason for his attack on Iran was territorial the Shatt al Arab, a waterway that empties into the Persian Gulf and forms the boundary between Iran and Iraq. In 1975, a militarily weaker Iraq had by treaty signed over to Iran partial control of the waterway, but after the fall (1979) of Muhammad Reza Shah Pahlevi and the resultant weakening of Iran’s military, Iraq seized the opportunity to reclaim the waterway.
Saddam also hoped to seize the western Iranian region of Khuzestan, an area known for its extensive oil fields. The Iraqi offensive was initially successful, capturing the port city of Khorramshahr by the end of 1980. Iranian resistance proved strong, however, and Iraqi troops had withdrawn from the occupied portions of Iran by early 1982. Nevertheless, Iranian leader Ruhollah Khomeini declared that Iran would not cease fighting until Saddam’s regime was toppled. Iran began a series of offensives, which proved successful enough to cause Iraq to resort to the use of chemical weapons, a tactic reviled by the international community.
The United States and several Western European nations became involved in the war in 1987, in response to Iranian attacks on Kuwaiti oil tankers traveling in the Persian Gulf. These attacks sullied Iran’s international reputation considerably, making it difficult for Khomeini to obtain arms. Finally, in July, 1988, Iran was forced to accept a United Nations–mandated cease-fire. Estimates of the number of dead range up to 1.5 million.