what is a realistic expectation from canada? 2% of gdp is a demand from american industry, not a substantive defence consideration.
the europeans have every right to prefer to maintain their own force, and if the americans want to insist on it, i'm sure they'll be happy to oblige.
canada's contribution should be entirely defensive. coast guard. norad. immigration. i'd be almost willing to provide a blank cheque on norad in return for an agreement to avoid further colonialism.
but, remember: the canadian oligarchs wants high oil prices, right now.