the reference case explicitly separates between a constitutional framework that is not reality but only exists in the ivory towers of the federal government, and actual reality on the ground in quebec. 

- can quebec secede unilaterally? that isn't a legal question, it's a political and a military question. can they or can they not?

- if they can, it means canada cannot stop them besides through a war of attrition, which is in contravention of international law and should be avoided. canada should seek to align the constitutional fantasy reality with the actual reality on the ground via negotiation.

- if they cannot secede unilaterally, canada can enforce it's constitution, which has rules for secession that make it virtually impossible, but this is a time wasting mechanism. if they could secede, they would do so unilaterally.

read the case yourself. it's well written.