Under the Abassids, Baghdad became a major center of Islamic learning and culture. Its doctors and hospitals were the best in the world; its scholars produced Q'uranic essays and masterful poems like the Arabian Nights. While the Abassids began as Shi'ites, once coming to power they embraced Sunni Islam, thereby starting a trend which would continue for centuries after their fall. There were brief moments when Shi'ites ruled this territory, but invariably the reins of power passed to Sunnis. The Ottomans who ruled this area for centuries were Sunnis; they gave favorable treatment to Iraq's Sunni Arabs and saw them as a buffer and bulwark against Shi'ite-dominated Iran. At best, Sunni rulers left the Shi'ites alone; at worst, they branded them as Ghulat (heretics) and subjected them to intermittent massacres and persecution.
While Hussein's Baath Party was secular, it was comprised largely of Sunnis drawn from the "golden triangle" between Baghdad and Mosul. Sunnis were disproprotionally represented in the government, and in the highest ranks of the Army. Hussein's government viewed leading Shi'ite clerics as a threat to his rule, and killed many while forcing others into exile. For their part, Sunni Arabs tended to be more loyal to Hussein and to see him as their best hope for maintaining privileged status. Some of the heaviest fighting for the advancing allies came in Sunni-dominated pro-Sadaam strongholds like Tikrit
The word "Sunni" is derived from the Arabic Sunnah, or custom. Sunni Moslems follow not only the Q'uran but also the Sunnah derived from the Hadiths - sayings of and examples from the life of Muhammed, compiled from various sources. The major difference between Sunni and Shi'a Islam is the status in which they hold Ali, the Prophet's cousin and husband of his daughter. Sunni Moslems consider him one of the great Caliphs; Shi'ites believe he was sinless and divinely inspired. This resembles the difference between Protestant and Catholic views of the Virgin Mary… and more than one scholar has compared Sunni Islam's relatively loose and free-form structure with Protestant Christianity.
While the Ulema (collective of Shi'a religious leaders) wield considerable power over their congregations, no comparable organization exists in Sunni Islam. Iraqi's Sunnis are generally more urbanized, and secularized, than their Shi'ite countrymen. This may prove disadvantageous in postwar Iraq, where religious leaders are playing increasingly important roles as political figures. In Iraq most Arab Sunnis are more inclined to identify themselves by their tribal affiliation, or by their connection to various political movements like Communism.
Despite efforts to link Hussein to Al-Qaeda, he generally showed little tolerance for fundamentalism, and cracked down on Islamic radicalism among Sunnis and Shi'ites alike. While there has been some radical Islamic activity among the Sunni Kurds, the Arab Sunnis have proven more resistant to recruiting efforts. This may change in the post-war chaos. Banned for decades, the Iraqi Islamic Party has recently reformed and has opened free health clinics and donation centers in an effort to fulfill charitable obligations and to recruit voters. The IIP is generally a moderate Islamist party which supports a multiparty democracy and condemns the use of violence. There are other groups which are less moderate; the city of Mosul in particular is seen as a hotbed of Wahhabism, the strict form of Islam practiced in Saudi Arabia.
After decades of oppression, there could well be civil war between the Shi'ites and the Sunnis. Fortunately, Hussein's commitment to secularism meant that his government was comprised not only of Sunnis but also of secular Shi'ites and others. The long and bloody Iran-Iraq War resulted in a need for soldiers, many of whom came from Shi'ite families. There is less Sunni-Shi'ite tension in Iraq than in Pakistan, Saudi Arabia or other countries with a substantial Shi'ite population. There has been considerable intermarriage, and many families, including Sadaam Hussein's, have both Shi'ite and Sunni branches. Still, it is not likely that Iraq's Sunni population will sit back idly if, or as, its Shi'ite majority founds an "Islamic Republic" on the Iranian model. (Neither will the occupying allies: of the five major figures in the U.S.-led "coalition," three of them are Sunnis and one is a secular Shi'ite). Hussein was able to use Shi'ite-Sunni tensions to his advantage; we will most likely not be able to do so. During the rebellion against the British, Sunni and Shi'ite joined forces to drive out the invader; fundamentalists in both camps may happily unite again against a common occupying foe.