But the weekend massacre of 16 civilians, mostly women and children, by a rogue U.S. soldier promises to undo whatever goodwill the Americans built — and to undo the fragile legacy of the Canadian army over its five-year Kandahar combat mission.
The Alaskan-based 3rd Battalion 21st U.S. Infantry Regiment — known as the Arctic Wolves — relieved Canadian troops in the troubled region last summer, allowing Ottawa to end the politically painful mission.
The Canadian military struggled to define its Afghan legacy as it left behind an unfinished war, one that cost billions of dollars and, at the time, 157 lives. One soldier has since died in the Kabul-centred training mission that took the place of combat operations.
The army's Kandahar reputation was partly built on trust established with locals in Panjwaii, long known for their hostility to outsiders.
Defence experts say that although Canada has been gone for almost a year, like it or not, the country's legacy is linked to the American massacre.
"Canada spent years of effort to create good will on behalf of (the International Security Assistance Force), and with the actions of one U.S. soldier, we're seeing all of that put at risk," said Walter Dorn, an associate professor and chair of international affairs at the Canadian Forces College.
Witnesses described how an American soldier who'd been guarding a U.S. Special Forces combat outpost wandered through the nearby villages of Balandi and Alokozi in the middle of night Sunday, broke into houses and indiscriminately shot residents.
"It's certainly not going to do our reputation any favours," said retired major-general Lewis MacKenzie. "There are a lot of projects, in a limited area, with the Canadian flag on it, both literally and physically."
But Defence Minister Peter MacKay was hopeful the Afghans will take the long view and recognize the West has been trying to help them.
"I think what is needed most here is perspective," MacKay said Monday in an interview with The Canadian Press.
"Let's not let it wash away all of the very real progress we have seen in that country." It was a "horrific incident, but it shouldn't overshadow everything else."
MacKenzie said that aside from the fallout and the potential impact on a post-2014 security arrangement with the U.S., questions should be raised about how a soldier wandered from a heavily fortified, well guarded outpost with no one noticing or raising the alarm.
"This story just doesn't add up," he said. "Talk about gifts to the Taliban. They just keep handing them propaganda presents."
The burning of copies of the Qur'an, an inadvertent helicopter strafing that killed four people in eastern Afghanistan, along with the 2010 murder of civilians for sport by a U.S. soldiers in Kandahar's Maiwand district have all taken their toll, said MacKenzie.
The Arctic Wolves have had a tough, nearly year-long tour.
The relative calm that characterized the final few months of the Canadian combat deployment evaporated not long after members of the 1st Battalion Royal 22e Regiment battle group returned home in July.
The unidentified soldier accused of the massacre arrived in theatre last December after completing three combat tours in Iraq.
According to the online website icasualties.org, the American unit has sustained at least five deaths, including the suicide of one soldier whose case has been become the focus of a high-profile series of courts martial among his comrades.
The Afghan district governor was also assassinated by the Taliban in a roadside bombing.
In an interview with The Canadian Press last July, the commander of the Arctic Wolves was optimistic, but underscored that building trust was paramount in a region that had long been controlled by the Taliban.
"The local Afghans are starting to believe that we are committed," said Lt.-Col. Steve Miller. "They are coming to shuras freely and you know there's a level of intimidation out there, but they're doing it anyway. It's a good sign."