Despite assurances that the new engagement in Iraq is not a combat mission, Canada could be on the hook to provide more support according to former prime minister Jean Chrétien.

"They are part of it. It is a done deal. They said yes to the coalition and they sent soldiers," Chrétien told Evan Solomon on CBC Radio's The House, referring to the Harper government's decision to send 69 special operations soldiers to northern Iraq as part of a coalition of nations fighting the Islamic State in Iraq and Syria, also known as ISIS.

The soldiers will act as advisers to Iraqi forces who are fighting to beat back the extremist organization, which has taken over great swaths of Iraq and Syria. They will not be involved in combat, according to Ottawa.

'You're in it or out'

The arrangement seems "unusual," Chrétien said.

"I hope they did not make a mistake. They are part of it. You know, I find it a bit unusual that they are part of it and then they say we're not quite part of it," he said.

"The other side knows we are part of it. Of course if they refuse to act, the partners will say you are not keeping your word," Chrétien said. "You cannot be a little bit in it. You're in it or out."

You have only to [look at] the way the Americans got involved in Vietnam. They started with a few advisers. - Jean Chrétien

Chrétien, while saying he didn't want to comment on the prime minister's decision, drew a comparison to the American war in Vietnam, which also started by sending in military advisers.

"You have only to [look at] the way the Americans got involved in Vietnam. They started with a few advisers," he said.

Adam Hodge, Foreign Minister John Baird's press secretary, said in an email to CBC News the minister's office wasn't interested in getting into a "war of words" with Chrétien.

"Canada's position is clear," he said.

"For Canada's part, we are supporting those in the front line against ISIS with the deployment of advisers and the delivery of equipment. We are also funding regional efforts to stem the flow of foreign fighters.

"We believe this is important, as to Canada, international terrorism remains the great struggle of this generation."

Chrétien refused to join the U.S.-led coalition that invaded Iraq in 2003 because it was not sanctioned by the United Nations.

That decision has been called one of the defining moments in his political career.

Canada did provide some informal support to the American military in Iraq, but that did not lead to a formal combat mission.

This time, more nations are willing to join the coalition. But it has also come with a promise that there will be no combat troops on the ground. The U.S., and now France, are conducting airstrikes in support of Iraqi and Kurdish forces.

Ground forces could be an option

Retired lieutenant-general Charles Bouchard, shown here in November 2011 in Ottawa, says airstrikes alone are not enough to fight ISIS. (Fred Chartrand/Canadian Press) But the promise of no combat troops is already being tested. This week in front of the Senate Armed Services Committee in Washington, the chairman of the Joint Chiefs of Staff, Gen. Martin Dempsey, would not rule out putting troops on the ground in Iraq if the airstrikes failed.

"My view at this point is that this coalition is the appropriate way forward. I believe that will prove to be true. But if it fails to be true and if there are threats to the U.S. I would of course go back to the president and make a recommendation that may include the use of U.S. military ground forces," he said.

Retired Canadian lieutenant-general Charles Bouchard also told CBC Radio's The House that airstrikes alone would not be sufficient in the fight against ISIS.

Airstrikes alone won't work

"Airstrikes in and of themselves are not sufficient," he said, pointing to the need for advisers, equipment, infrastructure and democratic institutions.

"There may be a need for boots on the ground, of course there may be. But before we go to that level I believe that it is wise to look at it and say, how do we help the people on the ground to deal with the situation themselves? To own the problem? Because I think this will provide a lasting solution," Bouchard said.

Bouchard commanded the NATO-led mission in Libya in 2011. That mission was seen as a success when it was over. It did not involve foreign troops on the ground.

However, Libya is now in chaos. The fear is that different tribal and armed groups will rip the country apart.

Bouchard said the military met its objective in Libya, but the world failed to follow through.

"Military action is only one part and it's not in and of itself," he said. "Is there political reform, economic reform, constitutional reform, social reform, educational reform — and I can go on for a long time — that has to be considered as well," Bouchard said.

Bouchard warned that if the world is going to get involved in Iraq, it has to decide how it will follow up and who is going to be there to provide assistance.

A clear mission

In Iraq, a clear objective is needed if the mission is to be a success, he said.

U.S. President Barack Obama has said the objective is to "degrade and destroy" ISIS. But Bouchard said, while he is sure military and political leaders are likely still discussing their final objective, more details are needed before an end state can really be agreed upon.

"Because to me defeating ISIS, what does that mean? Does that mean they have all been captured? Or have they been rendered ineffective by size? Rendered ineffective by other measures?" he said.

"Until there is that clear definition and understanding as to what will it be, what is that end state, then it is a difficult, it is difficult to predict an end state and date to the question," he said.

CBC Radio's The House airs Saturdays on CBC Radio One at 9 a.m. and on SiriusXM Ch. 169.