The reasons for violence in Iraq go back to the divisive policies of Saddam Hussein’s regime which had laid the seeds for political tension between the Shiite majority and the Sunni minority.

The situation was made worse by the catastrophic management of Iraq by the US-led coalition forces after the 2003 invasion, a free-for-all struggle for power between Iraqi political groups, and the emergence of Al Qaeda-linked Sunni extremists.

Was there Always Violence between Sunnis and Shiites in Iraq?

The media would sometimes have us believe that the current violence in Iraq is only the latest manifestation of some age-old struggle between Sunnis and Shiites. But in fact, the extent and the brutality of sectarian violence we’ve seen after 2003 is entirely unprecedented in Iraq, where various communities lived peacefully together for the most part of the 20th century.

Of course, communal tension increased at times of political volatility. In 1959, the ethnically and religiously mixed city of Mosul exploded in political violence. In 1991, the revolt in southern Iraq pitted Shiite rebels against largely Sunni special forces of Saddam’s regime. But never before have we seen such a prolonged armed confrontation framed exclusively in religious terms.

• Difference Between Sunnis and Shiites

How Saddam’s Regime Inflamed Sectarian Divisions

The "original sin" of the modern Iraqi state that came into being in the 1920s was its domination at the hands of a Sunni elite, in a country that was majority Shiite.

The perception that the top positions in the government and the army were reserved for the Sunnis was greatly reinforced under Saddam Hussein.

Cemented in the late 1970s, Saddam’s regime was controlled by a narrow group of Sunni officers from the city of Takrit. Of course, there were many Shiites in the ruling Baath Party, and many Sunnis who opposed Saddam. Regardless, political power became closely associated with religious identity, despite the regime’s secular nationalist ideology.

Things got worse when Iraq’s Shiite Islamist opposition (after 1979 egged on by the new Shiite Islamist regime in Iran) began openly to challenge Saddam – not because he was a Sunni, but because his regime was secular and authoritarian.

Saddam’s response was predictably brutal. By targeting Shiite religious leaders, the regime managed to alienate large sections of Iraq’s Shiite population, laying the seeds of resentment and sectarian mistrust that is so prevalent today.

Iraq after Saddam: Exclusion of Sunni Elites

The US-led invasion of Iraq in 2003 destroyed the old order, enabling Shiite Islamist parties to claim power in 2005 through free elections. The former Sunni elites were displaced by a new Shiite-dominated government. As rival Shiite politicians jockeyed for power, Sunnis felt sidelines, and many accused Shiites of collaboration with foreign troops.

At the same time, the US-led interim authorities made a catastrophic decision to disband the Iraqi army, putting thousands of officers out of work. Later, Iraqi government passed so-called “de-Baathification” laws, which barred former officials from the Baath Party from state employment and benefits.

Because Sunnis had dominated top military and government positions under Saddam, these measures affected them more than the Shiites. The majority-Sunni provinces in Iraq’s north-west took these developments as a direct threat to their community, an act of collective revenge by the Shiite leaders who they thought where working to monopolize all power in the new Iraq.

Former Sunni Baathists, tribal groups, Islamists and, increasingly, Al Qaeda-linked terrorists, took up arms against foreign troops and the new national security forces. The insurgency began.

Civil Conflict 2006-09: Struggle for Power

Islamist extremists among the dozens of Sunni insurgent groups began deliberately to target Shiite civilians. A bomb attack on a Shiite shrine in the town of Samarra in February 2006 triggered revenge attacks by Shiite militias, leading to open conflict in religiously mixed areas.

Millions of Iraqis fled abroad, as Sunni and Shiite paramilitary forces fought it out for the capital Baghdad, with tit-for-tat sectarian killings and ethnic cleansing of whole neighborhoods. Outside interference prolonged the carnage: jihadists from across the Muslim world poured into Iraq to fight for Al Qaeda, while some Shiite militias apparently enjoyed Iranian support.

The violence in those years was not solely sectarian in nature. Shiite militias loyal to the radical cleric Moqtada al-Sadr fought government troops and clashed with other Shiite Islamist rivals. Sunnis from the "Awakening" movement turned against Al Qaeda, accepting state payroll under US patronage, while others fought in the national army alongside Shiite soldiers.

By 2009, the government of Prime Minister Nuri al-Maliki managed to subdue most Sunni insurgents and Shiite militias, saving the state from complete disintegration. However, by this point the mixed Sunni-Shiite areas were devastated. Although only a minority of Sunnis and Shiites played an active role in the violence, the damage to the fabric of the society was done.

Current Situation: State Failings and Al Qaeda Threat

Today, major warfare has finished but Iraq remains an unstable place. Although Shiite, Sunni and Kurdish politicians cooperate in the central government, there is no real consensus on the future direction of the state. The oil production is booming, but the state is unable to create enough jobs or boost development.

There is a widely-held belief in the Sunni provinces that the government in Baghdad discriminates against them. This resentment creates a fertile terrain for the anti-Shiite propaganda of Al Qaeda-linked groups, such as the “Islamic State in Iraq".

Some Sunni leaders want equal participation in central government. Others want majority-Sunni areas to become a federal, autonomous entity within Iraq. A minority of extremists wants a total war against Shiites. Unfortunately, this minority is well-funded and well-organized, and there are plenty of unemployed young men willing to take up arms.

• Is Iraq a Democracy?

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