Canada's top military officer thinks that it is time to acquire armed drones, those unnerving robotic weapons that can seem to offer cost-free warfare, keeping the operators far from physical harm. "In my view, there's little point to having a UAV [unmanned aerial vehicle] that can see a danger but can't strike it if it needs to," General Jonathan Vance, the chief of the defence staff, told the Senate.
As a journalist and author who has watched these lethal aircraft emerge from a fog of secrecy in the United States, I'm impressed that the general has started a public conversation. Armed drones were used for more than a decade by the U.S. military and Central Intelligence Agency before Congress held its first public hearings. It took me four years and a court battle to get the classified legal opinions that approved the first deliberate killing by drone of a U.S. citizen, Anwar al-Awlaki, the charismatic preacher who condemned 9/11 but ended up as al-Qaeda's most dangerous recruiter.
Whatever one makes of the capabilities and dangers of drones, surely it makes sense for Canada to study the U.S. experience.
In a battle against a terrorist network, their appeal is clear. Coming into office, President Barack Obama was appalled by the carnage and cost of the big wars in Afghanistan and Iraq, which had done little to make Americans safer. He surprised his supporters by not just embracing but escalating George W. Bush's drone campaign in Pakistan and then expanding it to Yemen, Somalia and Libya. Drones seemed to offer the chance to pick off terrorists in twos and threes without turning more countries upside down.
And indeed, drone-fired missiles eviscerated al-Qaeda's core in Pakistan and knocked off the leaders of al-Qaeda's branch in Yemen, Mr. al-Awlaki included. Yet as so often in the U.S. war on terror, there have been unintended consequences:
Perhaps 10 to 25 per cent of those killed have been civilians. Though modest by the standards of conventional wars, the toll has produced a potent backlash and persuaded some angry young men to join the jihad cause.
Other countries resent the drones' violation of their sovereignty. Drone strikes have further darkened the United States' reputation, even among Pakistanis and Yemenis who have only contempt for al-Qaeda.
Drone operators, derided by fighter pilots as the "chair force," do not escape psychological harm. This is intimate killing: A drone pilot may watch a compound for hours or days before a strike, and suffer post-traumatic stress disorder afterward. When innocents are inadvertently killed, the emotional cost is still higher.
Drones cannot address the larger causes of terrorism. For example, strikes in Yemen have killed many al-Qaeda commanders, but because civil war has engulfed the country, the terrorist group has only grown stronger there, seizing entire towns and recruiting many fighters.
The saga of Mr. al-Awlaki, code-named "Objective Troy" on the U.S. kill list, captures many of the contradictions of an era shaped by the fear of extremist violence. But it holds particular lessons about drones.
The Obama administration considered his 2011 killing a major achievement; the President later compared it to a police officer taking out a gunman firing on an innocent crowd. But the Hellfire missiles did not eliminate Mr. al-Awlaki's most dangerous legacy: the massive collection of his audio, video and written work on the Internet.
In fact, by making him a martyr in the eyes of his fans, the drone strike enhanced Mr. al-Awlaki's authority with impressionable young people in the United States, Canada and Britain intrigued by the notion of jihad. They can find more than 60,000 videos by and about him on YouTube alone, and terrorism investigators have found his central influence in dozens of cases since his death, including the Boston Marathon bombings in 2013 and the San Bernardino, Calif., shooting last December.
There is a lesson here about the limits of lethal force in an ideological struggle. For all of its high-tech promise, the armed drone is only a piece of hardware, firing missiles into a conflict of immense human complexity.
Scott Shane is a reporter for The New York Times and author of Objective Troy: A Terrorist, A President, and the Rise of the Drone, which won the 2016 Lionel Gelber Award, given annually to the world's best non-fiction book on foreign affairs.