I could describe NORAD's evolution in four ages.
The first age was Soviet long-range aviation with gravity bombs, in such a way at that time in the late fifties that the air battle was going to take place just north of our border. That's how the air defence system was designed. Really, the only threat was in the aerospace domain. That was the only thing that was capable of reaching North America. Later, we talked about the introduction of ICBMs. That threw NORAD into a bit of a self-questioning mode. Was a conventional air defence system useful at that point given another domain, really, a ballistic missile flying through space? After much debate, there was a conclusion by both nations that in fact a conventional air defence system as a deterrent was a part of the deterrence to such an attack, so NORAD survived.
The second age came about as a result of the first generation of cruise missiles. That forced us to push forward to the north and defend further up north, where the battle zone, if you will, was pushed to our northern perimeter and into Alaska. Again, still the only domains that were really capable of being used to attack North America were aerospace and, in space, ballistic missiles.
The third age, 9/11, made us look inside. We know the story there.
We're now in the fourth age. The fourth age is the age of these advanced cruise missiles, with their very long range, which is challenging our ability to intercept and kill those vehicles before they can cause us harm. They can be launched now by our maritime platforms. Maritime avenues and maritime approaches are now a domain that is more prominent than ever before in terms of a threat to North America or a capability to reach North America. That is a big change.
While all this is going on, of course, you have cyber, which is happening every day. While I can't go into more detail, it is apparent that this is something that we're all concerned about from a continental point of view, starting from the national point of view.
As I get into this description of what we see from Colorado Springs, then certainly the maritime domain is something that we should look at expanding into.
Again, cyber is very complicated. I am not sure that we could reach a binational one on cyber, other than just co-operation and the exchange of information. We're still probably not mature enough to envisage a continental defence against cyber. It is very national in nature, and there are a lot of sensitivities and so on and so forth.
From the land perspective, while it's probably the last domain, we still don't see a current threat. I'm not talking about counterterrorism, which is something that is totally different, but a traditional symmetric threat to the land domain is probably something that we're not totally concerned about yet.
To summarize: aerospace domain, maritime domain, cyber, and land, and there are more as far as evolution is concerned.