Sweden and Switzerland are both in vulnerable locations. Technically, Canada has land borders with two countries, Denmark and the US. I don't anticipate an invasion coming through Hans Island, so we really only have a border with the US. Short of building a substantial nuclear deterrent force, we can't defend ourselves against the US and are entirely dependent on their lack of interest in conquering us. 

The only other country with the naval resources to invade Canada is the UK, and it's ridiculous to think they would. In other words, the only remotely plausible threat to Canada is the US. Since it is impossible to defend against the only plausible threat, why bother to defend at all?