OTTAWA -- The ghosts of Canada's last air war are likely to haunt its participation in the new campaign against the Islamic State of Iraq and the Levant.

The bombing campaign in Libya three years ago, hailed as a triumph on Parliament Hill, looks very much like the deployment that will unfold over the next few weeks in the Persian Gulf.

The force -- six CF-18 jetfighters, two CP-140 Aurora patrol planes and a CP-150 refuelling jet -- is almost identical to the one that helped NATO unseat dictator Moammar Gadhafi.

The mission -- to bomb targets in support of local ground forces -- as part of a multi-national effort is also eerily similar.

But there are some critical differences that have the potential to make the fight against ISIS more messy and politically painful.

The last time the mission was carried out under the defined structure and legal cover of NATO and a United Nations resolution; this time it is under the auspices of a U.S.-led coalition that is still working out its command and accountability structure.

In Libya, pro-Gadhafi -- or regime forces -- were readily distinguished, even when they tried to hide themselves. Islamic State fighters however, have the potential to be much more ghostly and indistinguishable from the civilian population, much the same way the Taliban blended in with Afghan villagers.

The uncertainty is being recognized in Canadian military planning and the possibility of opting out of some missions exists.

A spokeswoman for Defence Minister Rob Nicholson said late last week that Canadian commanders will take their day-to-day tactical direction from the coalition in terms of what targets to hit.

But, Johanna Quinney said, "the final decision to participate in missions will be retained by Canada."

The legal authority to drop bombs on suspected Islamic State targets is not covered in a status of forces agreement, she added, but in "diplomatic notes" to the government in Baghdad, which "has given Canada the authorization to conduct those activities on the territory of Iraq."

The spectre of wayward air strikes is already haunting the campaign to dislodge ISIS.

There have been reports that some U.S. bombing missions have killed civilians in Syria -- claims refuted by the Pentagon. Just a few days ago Australia acknowledged it had to call off a mission because of the fear of "collateral damage."

The human rights scrutiny is intense and -- in the age of social media -- immediate.

Following Libya, a special commission of the United Nations and the international group Human Right Watch conducted separate, detailed investigations into allegations that the NATO-led bombing campaign in Libya led to civilian deaths.

The International Commission of Inquiry on Libya resoundingly condemned both the pro-and-anti-Gadhafi forces for atrocities, but it didn't entirely let the western military alliance, nor its member countries, off the hook.

Similarly, the New York City-based Human Rights Watch wrote in 2012 to NATO and each of the countries that conducted bombing missions --including Canada --asking questions about targeting intelligence and post-action assessments, among other things, as it looked into nine cases of innocents being killed.

A trail of internal briefings among several departments show both Defence and Foreign Affairs paid extremely close attention not only to the human rights investigations, but to the political fallout of the campaign in allied countries.

In particular they watched Britain, where a parliamentary committee openly debated the fuzzy transition between the UN-mandated protection of civilians and what eventually morphed into deposing Gadhafi.

"The committee criticized the UK government's communication of the mission objectives -- i.e. regime change vs. protection of civilians -- it found that the international community was justified in its response to the situation in Libya," said a detailed Feb. 8, 2012 analysis prepared for both the Defence and Foreign Affairs ministers.

Unlike the U.K., there was no such formal reflection in Canada and the war Parliament opted last week to join in Iraq -- and by default Syria -- is even more hazy in its objectives.

When NATO went into the Libya campaign, it did so with "zero expectation" of death or injury to civilians, said a March 13, 2012 briefing for then defence minister Peter MacKay, one of several that year which tracked the human rights inquiries.

UN human rights investigators examined 20 air strikes and questioned five of them where there was a total of 60 civilians killed and 55 injured.

Separately, two other attacks where "no military targets could be identified" were examined, said the UN commission's final report.

The alliance "conducted a highly precise campaign with demonstrable determination to avoid civilian casualties," concluded the report, tabled on March 9, 2012 in Geneva.

But it urged further investigation, saying it was "unable to draw conclusions" whether the raids in question violated international law. The alliance refused to disclose which nation conducted the attacks.

Whether Canadians reviewed their own strike records remains a mystery. National Defence did not answer questions last week about either human rights review.