SHIITE Muslims represent about 55 percent of Iraq's population of 17 to 18 million. They are followers of the Shia branch of Islam, its name deriving from the Arabic Shiat Ali - followers of Ali, the son-in-law of the Prophet Muhammad. They split away from the mainstream of Islam when Ali failed to be named as the prophet's successor after his death in 632. The tombs of Ali and his son, the Imam Hussein, are both located in southern Iraq, in the cities of Najaf and Karbala. After the prophet, these two men are the most revered figures in Shia Islam.
Southern Iraq is the stronghold of the Shia, with Basra its key population center. About two-thirds of Basra's inhabitants, more than 1 million people, are Shiites.
There are strong religious, cultural, and family links between Iraqi Shiites and those in neighboring Iran. The Tehran government has allowed prominent Iraqi Shiite opposition figures to base themselves in Iran, and has given opposition groups political and material help. Most notable of the Iraqi exiles is Grand Ayatollah Muhammad Bakr al-Hakim, who heads the Supreme Assembly of the Islamic Revolution in Iraq - an umbrella group bringing together 12 Shiite groups opposed to Iraqi leader Saddam Hussein.
Hakim is the son of Ayatollah Mohsen al-Hakim who, until his death in 1970, was the spiritual leader of all Shiite Muslims. Hakim fled from Iraq in 1980, when the Baghdad government began to purge Shiite leaders in the south, accusing them of plotting against the regime. Three years later, Ayatollah Ruhollah Khomeini of Iran declared that Hakim would be the ``next ruler of an Islamic Iraq.''
Many Shiites in southern Iraq would like to see the creation of an Iranian-style Islamic republic. All Shiites want the end of Saddam's regime, especially after the savage methods used to suppress the latest rebellion. But a sizable proportion say they want simply a leadership change in Baghdad which would allow for democracy and greater freedom of expression.
Some Shiites remain detached from political life. Most prominent is Grand Ayatollah Abul Qassem al-Khoi, the most revered spiritual authority in Shia Islam.
The ruling hierarchy clustered around Saddam contains few Shiites relative to their numbers in Iraq. In a move that appeared belatedly to acknowledge this failing, the president announced last month that Saadoun Hammadi, the leading Shiite in the ruling Revolutionary Command Council, had been elevated to the office of prime minister. But Mr. Hammadi is a well-known ideologue of the Baath party, and the reaction among Shiites was that his promotion would have no practical effect on their lives.
Apart from the Supreme Assembly of the Islamic Revolution in Iraq, the other major opposition group is the Islamic Call Party, also based in Tehran. This group has been feared most by the government, and any Iraqi suspected of being a member could expect to face the death penalty.