Usually when you get a briefing from NORAD and they talk about the strategic threats from Russia and China, they tend to focus on the aerospace threat, so the fact that Russia is investing significant resources in strategic nuclear forces, or that they have global precision strike capability now. For China, it's the fact that they are rapidly modernizing their nuclear forces.
As far as Canada's subs are concerned, that's not something I can necessarily comment on, except that I would sort of borrow from the thinking of John Mearsheimer. The advantage that the U.S. has to Russia and China at the moment is that the U.S. has the freedom to roam, which Russia and China don't yet have. It's improving, but they don't have it. Any conversations that Canada has, being as we are one of the United States' most important allies, is how our growing capabilities will match their ability to keep that freedom to roam.