When a Canadian soldier dies in Afghanistan (as more than 150 have so far), it makes front-page news. In Ontario, a stretch of the 401 has been renamed the Highway of Heroes, and Canadians pay tribute by lining the overpasses from Trenton to Toronto.

Now cast your mind back a couple of millennia. In 216 B.C., 48,000 soldiers were killed in a single battle on a single day. The place was Cannae, on the Italian Peninsula, and the occasion was a battle in the Second Punic War between those imperial rivals, Rome and Carthage.

Not only did these 48,000 men - there were only male soldiers then - die in a single day, but they were butchered in what military historian Robert L. O'Connell calls a "massive knife fight." As he told me on a recent Ideas episode, those men, mostly Roman, were herded together and slaughtered by the cunning Carthaginian general Hannibal. O'Connell is the author of The Ghosts of Cannae: Hannibal and the Darkest Hour of the Roman Republic. There is no doubt in O'Connell's mind that the most hellish place on Earth that day was a patch of ground on the Italian peninsula. 

Military historians have a way of graphically presenting their facts. Based on what O'Connell estimates was the average weight of a Roman soldier - 130 pounds, or almost 59 kilograms - there was, on the battlefield, "6-7 million pounds of freshly slaughtered human meat." A feast for carrion, a "bonanza" for foxes, wolves, vultures and other rummaging creatures.

I bring these grisly details up to highlight this simple insight: for us in the West today, the entire meaning and calculation of war has changed. This is in no way meant to demean the sacrifice of a single Canadian soldier killed in Afghanistan, in most cases by an improvised explosive device (IED), a bomb or a mine. It is a tragedy.

But as O'Connell points out, 48,000 dead in one day in an ancient battle is 10,000 fewer than the number of Americans killed during the entire Vietnam War. (The Vietnamese dead, alas, were estimated at between one and two million.)

The West saw vast numbers of dead and wounded in its world wars in the 20th century. In the First World War, in the Battle of the Somme, there were 58,000 British casualties on a single day, one third of them killed in combat. Over four days at Vimy Ridge, 3,600 Canadian soldiers died and another 5,000  were wounded. All told, 67,000 Canadians were killed in the First World War.

For us in the West today, the entire meaning and calculation of war has changed.

I think I can safely say we would balk at duplicating these statistics today, even with a larger population.

A good part of this reluctance to accept casualties now, as the historian Edward Luttwak has pointed out, is that modern families are smaller. Today, in a common two-child family, the loss of one child would be more crippling than it was for larger families at the turn of the century. Back then, death was ever present. Children routinely died of disease and other causes. In this way, one child killed in a war would likely still leave a roomful of kids for parents to tend.

Needless to say, each life is precious. No one wants to sacrifice their child, even if their son or daughter willingly joins the military or volunteers to be posted to a battle zone. So, our definition of an optimal war is evolving towards one fought with the hope of not a single fatality.

This is not so far fetched. The no-fly zone in Libya - and the support for the rebels there - can largely be conducted from 20,000 or 40,000 feet. During the 10-week NATO bombing campaign against Serbia in 1999, only two  allied planes were shot down (two attack helicopters crashed while training). In the first days of the air campaign against Libya, the fact that one American plane crashed - supposedly by accident - made headlines. Imagine if one of our handful of jets operating over Libya were shot down? I think it's safe to say the arguments against the intervention would increase. Certainly questions would be asked, in the media and among politicians.

So, is this the future of war for us in the privileged West? A war with minimum - or hopefully no - casualties? (I say "privileged" because the civil war in Libya has resulted in many dead and wounded Libyans, as yet uncounted. In one out-of-the-way spot on the globe, up to five million people have died in the ongoing wars in the Congo.)

And how would a conflict without Western casualties be accomplished?

The answer is robotic war. That's the specialty of P.W. Singer, the author of Wired for War: The Robotics Revolution and Conflict in the 21st Century. In a talk at a TED (Ideas Worth Spreading) conference, he succinctly outlined his argument. At the beginning of the first Iraq war, the Americans had only a small number of drones. Now, they have more than 5,300, operating in various theatres, including Iraq and most noteworthy, Pakistan.

But not all wars will be fought from the sky. After all, sometimes armies need "boots on the ground." This will be accomplished by "killer systems and applications" - in other words, robot tanks and other vehicles right out of movies like Transformers.

Singer tells us that the current generation of robotic tanks are model Ts compared to what's in development. Tens of thousands of these "systems" will be operational in coming years. And the Americans aren't the only ones working on these robot devices; 43 other countries are developing them, too.

How will that change the nature of war? Drone pilots in Nevada conduct their video wars on 12-hour shifts in air-conditioned comfort on military bases half a world away from the theatre of war. Afterwards, they go home for dinner and help their kids with homework. This is truly war as video game.

Of course, bomber pilots have often been remote-control warriors, letting bombs loose from great heights (except for the important fact they might get shot down by anti-aircraft fire). But now, as a drone pilot or a robot tank operator, the only way these soldiers will get killed is if they die in a traffic accident commuting to or from a hectic day's work.

So, what are the implications of this kind of high-tech, almost clinical war? According to Singer, there are three important considerations.

First, it will be easier for a Western country to commit to a war when nobody comes home in a body bag (on your side, that is).

Second, our enemies may see us as cowardly, as one Lebanese journalist told Singer while watching drones flying over Beirut. The high-tech, Western way of war could be regarded by our enemies as unmanly, even craven. By in trying to rise above a ground war, the message we're giving our enemy is that if they manage to kill even a handful of our soldiers, we won't have any stomach for a real, sustained fight (which is what Osama bin Laden believes).

The third implication is also scary. Militaries aren't the only people who want to automate war. So do terrorists and other "non-state actors." The technology will be available for purchase, off the shelf. Arms merchants are always willing to sell to anybody for the right price.

All told, robotic technology will both desensitize and further scare us, if it is used against civilians in the West. Welcome to the wars of the 21st century,  coming to a computer screen near you.