It isn't a zero-sum calculation. A US retraction of commitment does not necessarily leave Canada threatened in an existential way. The issue is that if the current rules-based international order bulwarked by liberal democracies goes down the tubes to some degree, your standard of living (and mine) will be affected and the world will become a substantially worse place.

Quite honestly if the government properly manned the existing CAF force structure and gave it the full complement of weapon systems that even its own doctrine calls for - that would be a dramatic improvement. Much of the current CAF outside NDHQ and other headquarters amounts to a hollow force and window dressing to its stated capabilities. Part of that, as job number one, would be putting defence procurement in one department (or an entirely new one) with the authority to get it done and holding one minister responsible for any bungling.