Nouri Al Maliki’s fitful departure from Iraq’s premiership recalled many other cliffhanger exits by unpopular political leaders. His leaving did not come a moment too soon for the many Iraqis who have laid all of the country’s current troubles at his doorstep.

Al Maliki, according to this view, was endlessly divisive, driven by authoritarian tendencies, lacking in elementary political skills, and incapable of leading an army in disarray. But his greatest failure was his inability to grasp that successful governance in Iraq requires reaching out to other communities, notably the Sunnis and Kurds.

Instead, Al Maliki ordered preventive arrests of young Sunni men, supposedly in anticipation of their defection to terrorist groups, and hounded his political opponents, in some instances driving them out of government (and in one case into exile).

No doubt, much of this narrative has a basis in fact. But if it were the whole story, the mild-mannered, western-educated prime minister-designate, Haider Al Abadi, would have an easy task in stitching things back together. After all, Iraq’s Sunnis would have every reason to support Al Abadi now that Al Maliki has gone.

In fact, Al Abadi will have his hands full. Iraq has been falling apart not just because of Al Maliki’s failure to reach out to the country’s 20 per cent Sunni minority, but also because of the Sunnis’ failure to embrace a country whose majority political expression is Shiite.

The Islamic State of Iraq and the Levant (Isil), to take the most obvious example, is not a consequence of Al Maliki’s failure to engage in Sunni outreach. There is little evidence that the Sunni Isil has the slightest interest in outreach by any Shiite leader. What it wants is the destruction of the “apostate” Shiite community’s members and shrines. Murky as Isil may be, its position on this point is unambiguous.

Though much of the Isil leadership and many of its recruits are Iraqi, the group emerged as a well-funded and well-equipped force during the civil war in Syria. But Isil was not content to eliminate Alawite power there; rather, it has taken aim at any challenge to its authority as the true representative of the Sunnis in the Levant and beyond. Thus, it attacked elements connected to the Muslim Brotherhood, Egyptian Salafis, and the Free Syrian Army with great ferocity — so much so that the Syrian army sometimes let them do its work.

Isil, like many such groups before it, may yet vanish in the desert, leaving only its victims’ families to recall the crimes it committed. But what will not be forgotten, especially among the Kurds and Shiite Arabs, is the deafening silence of the Sunni world. Rather than denounce the Isil’s barbaric behaviour, members of the Gulf Cooperation Council (GCC), the pre-eminent regional organisation of Arab states, issued a series of tepid statements denying support for it in the wake of its entry into Iraq.

The GCC countries mostly blamed Al Maliki for not doing more to address Sunni political frustration, as if that explained Isil’s campaign of mass murder.

Similarly, neither Sunni leaders in Baghdad nor tribal leaders in western Iraq (some of whom have accepted Isil payments) have done much to denounce the group. Instead, Iraq’s Sunnis have cynically used the Isil’s invasion to enhance their leverage in the ongoing process of forming a new government.

It is time for Sunnis in Iraq and beyond to speak and act with much greater clarity and consistency on this existential threat to civilisation in the cradle of civilisation. For starters, aid to Isil, some of it emanating from the Gulf, needs to stop. From 2005 to 2008, interdicting foreign fighters and assistance to Isil’s predecessor, Al Qaida in Iraq, contributed significantly to quelling the Sunni insurgency.

A solution that neutralises Isil also needs to provide a way forward in Syria. Such a solution will need to be multidimensional, and will probably include air strikes against Isil in Syria itself — an eventuality to which no one is looking forward.

But Syria will not be stabilised with air strikes alone. There must be a renewed diplomatic push to build consensus — first among external powers, and then among the warring parties — on what Syria will look like in the future. Will it be a federated republic? A system based on cantons? Perhaps it should have a bicameral parliament with a communal-based upper house that could veto what a Sunni-majority lower house enacts.

Articulation of future political arrangements in Syria, as pie-in-the-sky as it may seem today, is probably the best way to help the country’s beleaguered moderate opposition and expose the rejectionists. President Bashar Al Assad should not be a part of Syria’s future, but that issue can be deferred for the time being — while well-functioning channels of communication with the Alawites and others who continue to fight for him are established.

There will be those who say that this should have been done two years ago. But we should not console ourselves with the thought that late is better than never. Given the Syrian civil war’s momentum and complexity, it is likely that fighting will continue two years from now, when some will no doubt look back and say that some other path should have been taken — you guessed it — two years ago.

— Project Syndicate, 2014.

Christopher R. Hill, former US Assistant Secretary of State for East Asia, is Dean of the Korbel School of International Studies, University of Denver, and the author of the forthcoming book Outpost.