Time will tell whether NATO's multi-year mission to train Afghan forces was successful or not.

But at least Canada and other participants can say that in Afghanistan, they tried hard to build a true national government, national army, and national police.

In Iraq, they have largely given up. And in Syria, they never even got started.

The central contradiction of Canada's training mission in the war against ISIS is that, while it is officially there to defend Iraq's national integrity, it is doing so by supporting a separatist militia that does not take orders from Baghdad.

Moreover, while the Kurds have shown their mettle in defending and even retaking Kurdish areas from ISIS, there are few reasons to believe the Kurds will ever pursue an offensive into the historically non-Kurdish areas that are now the Islamic State's heartland.

So the first question to ask when looking at Canada's training mission in Iraq is: Why aren't we training the Iraqi army?

Army ruined by incompetence

When the Iraqi army was routed by ISIS in a humiliating defeat at Mosul in 2014, it abandoned vast quantities of arms and equipment, including 2,300 U.S.-supplied Humvees worth over a billion dollars.

A less visible waste, but one that pained Washington just as much, was the $25 billion the U.S. had spent training the Iraqi army since 2004.

Iraq's army continues to be a weak and unreliable force, depending heavily on the Iranian-backed Shia militias who ultimately kept ISIS out of Baghdad.

Many of its officers are currently facing courts martial for cowardice in the losses of Mosul and Ramadi.

U.S.-led coalition has already invested heavily in training Iraqi troops 2:38

A good investment?

It is entirely understandable that Canada would not want to invest its training efforts in the Iraqi army.

And yet a non-sectarian Iraqi army would be the only force with a chance of being accepted in the Sunni-majority Arab areas of Iraq where ISIS has gained a foothold.

Kurdish forces have little interest in risking their lives to "free" those areas, and little hope of being accepted as liberators.

Jeremy Binnie, a defence analyst with Jane's Defence in London, says Canada's Kurdish militia proxies face the same limitations as Iran's Shia militia proxies.

"There are limits to how far Kurdish forces can go into Sunni Arab territory, thus there are limits to how much they can contribute to defeating the Islamic State. So if you're going to do your training with the Kurds, that's really just about containment. It doesn't take the battle to Islamic State in any major way."

Prime Minister Justin Trudeau speaks to reporters about Canada's engagement to fight ISIS 2:49

No trainers in Syria

There's an even bigger problem with the notion that training local forces will be enough to defeat Islamic State.

British Prime Minister David Cameron made the point just days ago as he pressed his own parliament to extend Britain's bombing mission from Iraq to Syria.

"It is in Syria, in Raqqa, that [ISIS] has its headquarters and it is from Raqqa that some of the main threats against this country are planned and orchestrated," Cameron said. "Raqqa, if you like, is the head of the snake."

And yet Canada's training efforts are focused only on Iraq. Western efforts to train proxies in Syria have ended in fiasco.

Last month, the U.S. suspended its efforts to train "moderate" Syrian rebels after spending nearly $500 million.

The program intended to create a fighting force of 5,400 men. It produced only 60, who surrendered some of their U.S.-supplied weapons to al-Qaeda shortly after entering Syria from their training program in Turkey.

Kurdish fighters watch their enemy in the early morning hours as they fight the Islamic State group in Sinjar, Iraq, on Nov. 13, 2015. (Bram Janssen/Associated Press)

Is training ever successful?

"Our track record at building security forces over the past 15 years is miserable," says Lt.-Gen (ret.) Karl W. Eikenberry, who commanded coalition forces in Afghanistan from 2005 to 2007, and subsequently became U.S. ambassador to the country.

The U.S. spent $65 billion there, but has had to repeatedly delay the departure of its own troops because the Afghans still need help.

U.S. Special Forces trained their counterparts in Yemen for years, but it took only weeks for those forces to disintegrate in the face of Houthi militiamen earlier this year.

In Mali in 2012, an officer trained by Green Berets to fight al-Qaeda in the Islamic Maghreb instead deposed the democratically-elected president in a coup. Al-Qaeda overran much of the Malian hinterland, until French troops arrived to stop them.

The notion that Canada is uniquely well-suited to provide training is based on its experience in Afghanistan, where the question of whether local forces can defend their own country will only be answered after foreign troops leave.

But experience suggests that if soldiers don't trust their officers, if they haven't been paid because corrupt bureaucrats have purloined their salaries, and if they don't really identify with the cause or the country they're fighting for, they're unlikely to be much use when the shells start flying.