At the end of WW II Canada had the world's third largest navy. I get that a military spending is like insurance: if you don't need it it's wasted money, and there are always other things to spend your cash on. But Canada really seems to have allowed its military to languish to an unnecessary degree.
And why wouldn't you? When you're friendly with the neighbors next door to the south, and they own the world's premier military and love to show it off, why wouldn't you outsource military spending to that neighbor? There are plenty of nice things you could buy with the savings.
I suppose, if you're willing to believe your neighbor to the south will always be willing to come to your aid when you call. Even assuming your interests don't conflict, that doesn't mean they'll always coincide.
I wonder if, for example, the US would be willing to threaten Chinese fishing boats to protect Canadian fisheries, should it come to that. I'm thinking probably not.
Also, the amount of influence you have in influencing policy in these international military coalitions depends in large part on how much you bring to the table. It's rarely, IMO, a good idea to get involved in coalition warfare, but you'd like to have the option if your country's interests would be served in doing so.
