canada

That might be the plan they have in their heads, but the reality is that the west simply lacks industrial capacity to do that right now. Russia alone outproduces all of NATO militarily, and China absolutely dwarfs Russia. Iran was able to easily overwhelm Israeli air defenses, and the US is unable to replace them. Furthermore, the US military industry, such as it exists, can't even produce key things like rare earth magnets or antimony needed for weapon and ammunition production. The whole idea of having a WW3 without having domestic supply chains is fantastical in nature.