Iraq's volatile politics have been a struggle for power by religious, tribal and ideological factions throughout the country's history. In whatever political order may emerge should Saddam Hussein be toppled, all the disparate groups will seek to play a role.
King Faisal, the first monarch of modern Iraq, recognized the problem of the many divisions within the society. "Regrettably, I can say there is no Iraqi people yet, but only deluded human groups void of any national idea," he wrote shortly before his death in 1937. "Iraqis are not only disunited but evil-motivated, anarchy prone and always ready to prey on their government."
Faisal had a part in the problems he described. He was installed as Iraq's king by British colonial power in 1921 in reward for his Hashemite family' support against the Turks in World War I. Faisal had no family ties or historical roots in the country, and Iraqis showed no desire to bow to a British puppet.
Renowned British diplomat Gertrude Bell was able to help persuade the British that Faisal was the best choice in part because of her links to tribal leaders.
Tribal chieftains, who own huge estates and are backed by hundreds of thousands of men under arms, were major powers. No Iraqi government could have functioned without co-opting or subjugating them.
When the southern tribes rebelled in 1920, shortly after Iraq was put under British mandate, it took brutal force, bribes and cunning diplomacy to put down the five-month rebellion. Britain lost some 2,500 soldiers, and the total losses among the rebels were unknown.
Today, with the prospect of a civil uprising high if the United States wages a war to take out Saddam, the Iraqi leader is pumping billions of dinars (million of US dollars) into the newly revived clan system and trying to force tribesmen to swear allegiance to him.
Another cause for instability in Iraq was Britain's decision to favor the Sunni Muslim Arab minority about 20 percent of the population over the Shiite Muslim Arab majority and ethnic Kurds who had rebelled against British rule in 1920.
Shiites had distanced themselves from Ottoman rule dominated by Sunni Turks. Iraq's Sunnis embraced the Ottoman system and advanced within it, putting them in a strategic position when the British arrived.
With British help, Sunni Arabs imposed their control first on educational institutions, then the army and later on the economy, all the while alienating the majority population. The Sunni elite used military force to repress rivals and maintain political supremacy.
After Iraq's defeat in the Gulf War in 1991, the Shiites arose in revolt against Saddam's rule, but the Iraqi leader's Republican Guard put down the rebellion, leading to tens of thousands of deaths.
Today, the Shiite opposition is insisting its share of power in any post-Saddam Iraq match its 65 percent share of the population in the country of 22 million.
Shiite aspirations worry other Iraqi minorities and the country's mostly Sunni Arab neighbors. The main Shiite opposition group, the Supreme Council for the Islamic Revolution in Iraq, is based in Iran, and the possibility of Shiite-majority Iran's influence over Baghdad also concerns Iraq's Arab neighbors.
The Kurds, in northern Iraq, also are worrisome to the neighbors. Since Iraq's 1932 independence, the Kurds, some 20 percent of the population, have fought for broader autonomy in their impoverished enclave.
Thousands of Kurds were gassed by Saddam's forces and their villages were bulldozed in what their leaders call ethnic cleansing campaigns in the 1970s and '80s. After the Gulf War, the Kurds again arose in revolt.
Today, the Kurds' demand for a federal system is raising suspicions they harbor secessionist intentions which worries neighbors Turkey and Iran, both of which have large Kurdish minorities.
The Sunni-controlled army also played a major, and often disruptive, role in politics. Iraqi history was marked by a series of military coups before Saddam took control of the whole country in 1979 and turned it into an autocracy.
Several exiled generals already are angling for a role for the army in a future, post-Saddam Iraq. Numerous political groups that existed before the advent of Saddam's regime including communist, liberal and Islamic parties are expected to try to reorganize in a future Iraq.
Saddam subordinated the army, the security forces, other elements of the state bureaucracy and a large sector of society under his Baath Party, which espoused secularism, socialist economics and a pan-Arab ideology. Today, the Baath party claims some 1 million members and sympathizers.
Some Iraqi opposition groups have urged dismantling the Baath apparatus and even bringing senior party officials to trial for the regime's atrocities. But others have urged clemency and reform of the party maintaining it is the country's only viable political organization.