Skip to main content

How do you put a price on dodging nuclear winter?

The question gets less absurd by the day, with North Korea and the U.S. locked in a standoff full of wild provocations, and global foreign ministers having gathered in Vancouver on Tuesday to discuss sanctions on the Hermit Kingdom.

Hawaii knows the subject isn't academic; a false alarm there on Saturday convinced many of the islands' residents that they were about to be killed by a ballistic missile. The accounts of mass panic that emerged from the usually laid-back Pacific state made vivid how cataclysmically awful such an attack would be, even before the bombs touched down.

And so, all of a sudden, an old, vexed debate has new currency: whether or not Canada should join the U.S. missile-defense shield. The Trudeau government has repeatedly flirted with the possibility. Now's the time for a decision.

On both sides of the 49th parallel, the shield is more opined on than understood. For one thing, it's not really a shield. More like a bulletproof vest, in that you still really don't want to get shot while wearing it.

The program Canada would be joining is called the Ground-Based Midcourse Defense system. It can track incoming missiles with radar and, in theory, shoot them down with a cluster of "interceptors" – rocket launchers, basically – mostly located in Alaska.

The system is far from foolproof. In testing since 1999, under conditions more or less choreographed for success, it has shot down 10 of 18 targets. That's not a great ratio, and it's a frighteningly small sample size.

So, on a good day, Canada would be getting a 60-per-cent chance of knocking a ballistic missile out of the air if it joined the U.S. shield. That's an awful lot better than no chance at all – but only if you think we're at risk.

Some people don't think we are; that a Canadian city being hit with a missile from North Korea is too unlikely to worry about. But there are scenarios in which it's imaginable.

Kim Jong Un and his military claque might want to show they can reach North America without hitting the U.S. directly, and aim for somewhere remote in Canada. The people who study these things call us a possible "demonstration target." Think of it as a shot across the Bow River.

Or imagine a missile bound for Seattle that goes off course towards Vancouver. It's not hard to, given the Kim regime's record in target practice.

We may well hope the U.S. would protect us from an ICBM, but that's not their policy, Canada's Lt. Gen. Pierre St-Amand told a Commons committee in September.

If it came down to it, the U.S. might be feeling generous. But the officers on duty would have to make up their minds quickly. An ICBM arrives terrifyingly fast – likely between 25 and 35 minutes from Pyongyang to Vancouver, with radar only determining the target well into the missile's journey. U.S. officers would have very little time to decide whether or not Toronto was worth saving.

Then again, if safety was the only concern, the case for joining the U.S. system would be straightforward. Cost is a factor, though, and the prospective price tag makes some balk. This is one reason the NDP opposes the scheme.

The trouble is, we don't know exactly what joining would cost. On the high end, if we wanted our own interceptors, the Canadian academic James Fergusson, citing U.S. defence officials, says the bill could run as high as $10-billion. Then again, it might be possible to strike a much cheaper deal, in which Canada provides radar capability in exchange for a U.S. promise to have our back.

Spending billions to defend against a remote contingency may seem wasteful. On the other hand, conventional cost-benefit thinking wobbles here: In the event that Pyongyang did target Canada, it would be worth roughly all the money in the world to have a chance of protecting ourselves.

That's why the Canadian government should find out what's on the table, and open discussions about joining the missile-defense program. For years, the Conservatives have been too gung-ho about this limited backup plan, and the NDP too squeamish. The Liberals, who have refused to stake out a coherent position either way, have a chance to be the party of sober, reasoned leadership on this issue.

Of course, we must keep trying for a diplomatic solution to the North Korean crisis. But sometimes you have to conduct diplomacy while wearing a bulletproof vest.

Interact with The Globe