The war will continue. Prime Minister Stephen Harper made that clear this week when he announced that Canada will extend and expand its military operations against Islamic State fighters.

The decision still needs to be rubber-stamped by the Commons. But that’s a formality. To all intents and purposes, we have re-enlisted for another tour.

Yet fundamental questions remain about this war, Canada’s third in 14 years. Here are five.

First, what is the war aim? What do we hope to accomplish?

U.S. President Barack Obama says the aim is to “degrade and ultimately destroy” the Islamic State, sometimes known as ISIS. Foreign Affairs Minister Rob Nicholson says Canada’s aim is to “degrade and destabilize” ISIS.

It is hard to know what any of this means.

Is it sufficient to drive Islamic State fighters from the towns and cities they control in Iraq? Or does victory require driving them out of Syria as well?

If this turns into a long-run guerrilla war, such as the Taliban continues to wage in Afghanistan, does our part in the struggle continue indefinitely?

Is Ottawa’s primary aim to protect Canada from ISIS-inspired terrorists here at home? If so, bombing Iraq or Syria may not help.

Indeed, as Parliament Hill shooter Michael Zehaf-Bibeau made clear in remarks he recorded before his rampage, such actions may well encourage more terror attacks here.

Second, with what do we propose to replace ISIS in Iraq and Syria? Whose regional interests are we serving in this war?

This question too is not easy to answer. In theory, Canada is in Iraq to aid that country’s central government. In practice, we are helping the country’s Kurdish minority which, over time, hopes to create an independent state that could include parts of Iraq, Syria and Turkey.

Ottawa doesn’t like to talk about it, but some Kurdish fighters aided by the West are linked to a group that Canada calls terrorist.

In practice, we are also aiding Iran, which is arming and mobilizing Shiite militias to fight the Sunni fighters of ISIS.

And of course, we are aiding the Syrian government of President Bashar Assad in his fight against the Islamic State.

A case could be made that under present circumstances it is in Canada’s interest to ally itself with a brutal Syrian dictator, a theocratic Iranian regime and a nascent Kurdish national liberation movement.

But we should at least be clear that this is what we are doing. And we should also think out what will happen if this unlikely coalition succeeds.

Third, how far are we willing to take this war? Islamic State fighters have emerged in Libya. Boko Haram terrorists in Nigeria have allied themselves with ISIS. There are even suggestions that ISIS is operating in Afghanistan.

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Are we prepared to take on the Islamic State in these countries as well?

Fourth, how do we avoid making things worse? Certainly, the West doesn’t have a good record here.

America’s arming of Afghan mujahideen in the ’80s produced the Taliban. The U.S.-led war to remove Saddam Hussein from Iraq ultimately gave the world the Islamic State.

The NATO air war against Moammar Gadhafi left Libya in tatters and encouraged the growth of terror groups across North Africa.

In this war, according to the United Nations Human Rights Office, ISIS fighters may have committed war crimes and genocide in Iraq.

But the UN agency also found that Iraqi forces battling ISIS may have engaged in extrajudicial killings and torture.

Fifth, once in this war, how do we get out? Former prime minister Jean Chrétien has warned against embarking on the slippery slope. He should know. His 2001 decision to send Canadian troops to Afghanistan started us on 12 years of war there.

In Iraq, mission creep has already begun. Ottawa initially promised that Canadian military advisers sent to Iraq would neither accompany Kurdish soldiers to the front lines nor engage in combat. Now the advisers do both.

It is worth remembering that the Afghan War was initially pitched as a battle against a brutal and barbarian enemy. Now the U.S. is now trying to facilitate a negotiated peace deal with those same brutal barbarians.

Is this foreshadowing? In 14 years, will we be talking peace with the Islamic State?