Yes. Deterrence is much, much less expensive than war.
Not enough people are thinking about what international security will look like after the usual members of coalitions of the willing have become, in the estimation of countries inclined to get frisky, weaker.
Canada and the US are already doing a lot of borrowing, paying a lot of money to bondholders, and mostly governed by parties determined to continue spending and put domestic spending ahead of international security spending. There's no fiscal freedom of manoeuvre right now; there will be less in the future; no-one can reliably predict what happens if current spending trends continue other than to assert that they can't. I suppose it's a kind of indirect strategy malign foreigners might employ: encourage more deficit spending by buying bonds, maybe making a small profit while strangling our fiscal capabilities.