If Osama bin Laden were still alive today, he might have watched the scenes of jubilation as Iraqi forces liberated of the city of Mosul from the so-called Islamic State this week and ruefully mused: "I told you so."

Among the tactical and strategic differences that divided bin Laden's al-Qaeda organization from ISIS was his belief that the birth of a caliphate, or Islamic state, could not be rushed or forced. "If our state is not supported by the proper foundations," he wrote in 2010, "the enemy will easily destroy it."

Al-Qaeda never declared the establishment of a new caliphate, because bin Laden knew the consequences of losing that state would be crippling.

ISIS leadership wasn't convinced. When Abu Bakr al-Baghdadi announced a caliphate from the Grand Mosque of al-Nuri in Mosul three years ago, he made the perceived strength of his movement dependent on the expansion and preservation of that caliphate. It was no longer enough to be an insurgent or terrorist group. The Islamic State of Iraq and Syria called itself a "state" and had to act like one. It would control territory, or stand exposed as a sham.

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Now Mosul, mostly rubble, is held by the Iraqi government. The minaret of the al-Nuri mosque is toppled, by the Islamic State's own hands. And Baghdadi himself may be dead.

The likely repercussions are every bit as devastating for ISIS as bin Laden predicted they would be — and indeed in the months and years to come, al-Qaeda may benefit as international jihadists look for a new home.

But the defeat of ISIS in Mosul nevertheless warrants the satisfaction it has provoked in Iraq and elsewhere. This is a victory for Iraq, and for Iraq's international partners — including Canada.

Prime Minister Justin Trudeau's foolish promise to withdraw Canada from combat operations against ISIS is only partially redeemed by his breaking of that promise — and the verbal gymnastics he has performed to pretend that he hasn't. Trudeau recently described a record-breaking kill shot by a Canadian sniper as "entirely consistent" with Canada's supposedly non-combat role in Iraq.

But this victory may also be a fleeting one if Iraq does not seize the opportunity it presents.

Making victory last

ISIS has slaughtered Sunnis by the hundreds and displaced them by the thousands, but their greatest hatred and violence is directed against those belonging to other faiths: Shia Muslims, Christians, Yazidis and others.

And while ISIS ruled by terror, it drew some support from Sunnis who felt abandoned by a government in Baghdad, which they believed discriminated against Sunnis and cared only for Shias.  

It's these people that Iraq must now bring onside if it is to have any hope of making this victory last.

There are reasons to worry. Part of the offensive against ISIS has been carried out by mostly Shia militias known as the Popular Mobilization Forces. Many are backed by Iran and seek to spread Iranian and Shia influence in Iraq. Iranian authorities boast about the role these militias have played. Deputy chief of Iran's armed forces, Brig. Gen. Massoud Jazayeri, this week described the liberation of Mosul as part of a larger American "failure" in the region, according to Iran's Fars news agency. 

Iraqi Prime Minister Haider al-Abadi has a good relationship with Washington, but there will be parliamentary elections in Iraq next year that may see him lose power to a candidate who is closer to Iran. That would mean a decrease in American influence in Iraq. But the more acute and immediate struggle will be within Iraq itself.

The Iraqi government repeatedly failed to empower Iraqi Sunnis following the overthrow of Saddam Hussein's Sunni-favouring dictatorship in 2003. These mistakes contributed to the sectarian bloodletting of 2006-08, the insurgency that followed America's withdrawal in 2011 and ISIS's lightning offensive in 2014 that nearly shattered Iraq.

But because the terror group ignored bin Laden's advice and over-reached; because Iraqis, with resolve and bravery, fought back; and because Iraq has the help of an international coalition of allies, it recovered, and has now won an opportunity to finally build a non-sectarian state worthy of the sacrifices its citizens have made.

Iraq must do so to prevent ISIS — or some future spinoff jihadist outfit — from yet again establishing roots among the country's disenfranchised Sunni Arabs. It may not get another chance.

This column is part of CBC's Opinion section. For more information about this section, please read this editor's blog and our FAQ.