If US foreign policy formulation is now, with reference to military intervention in foreign civil wars,  to unilaterally, on the fly, turn 180 degrees (sometimes followed by a further 180-degree turn) with scant notice to friend and foe alike (making bellicose declarations at each stage), Canada will have little reason to fully partner in such policies.

Instead, we like the other allies will make vaguely supportive statements (where the most recent US zig or zag has some merit) or vaguely equivocate (where we want to distant ourselves without a diplomatic dust-up with the US).

Having ample experience over the past 120 plus years dealing as junior partner of the UK or US, Canada is skilled in giving 'support short of aid' where we see no reason to offend or aid in an international initiative of our senior 'Great Power' ally (as well as fully supporting or declaring that we will not support where circumstances warrant).

Trudeau's statement implied the limit of Canadian future support.