Canada does not need to have the capability to solely defend it's borders as it's in NATO. That's the point of the alliance. In return, we've made a commitment to spend 2% of GDP to have a military capable of meeting our NATO commitments -- including defending the borders of other NATO countries. As many of pointed out, the cost to us to be capable of defending Canada alone would be far greater. So, there's really no excuse for not meeting that commitment other than it is spending that doesn't provide much political return (which is a terrible 'reason'). If someone has a practical alternative to the NATO alliance for Canada's defence that will be 'cheaper' than 2% GDP, I'd love to hear it. Otherwise -- time to step up.