That is my analysis of the entire system invented or proposed by the Supreme Court based on an unwritten, underlying constitutional principle. The system in itself, if the Commission has an advisory function, is perfectly valid and defensible. But from there to force Parliament to justify itself, not to the electorate alone, but in relation to the report of a commission, before the courts, and ultimately the Superior Court, the Federal Court or the Supreme Court...
As for the reasonableness of choices which are political, this comes as a surprise to me. As a member of Parliament, you are right to consider that the powers of Parliament are being whittled away, even though the Supreme Court has said that this is an advisory commission. In fact, I believe it was a Quebec Superior Court or Court of Appeal which ruled that a judge may not order Parliament to do something. A justice of the Superior Court had ordered the National Assembly to pass legislation to implement something, and the Court of Appeal said no, that this would be completely unconstitutional.
So, we have to come back to reality. I believe that when the government has defensible reasons to present a different opinion, it should do so and stick to its guns. Even the Supreme Court, in the 2005 ruling, did nuance somewhat the strictness, I guess I could say, of its opinion in the 1997 Reference. Mr. Cotler is not here now, but I think he would agree. When you read the two rulings and the overall arguments made by judges in every single one of the provinces, well, it's clear that there is a huge amount of literature and case law on what exactly can be considered reasonable.
You are right to say that Parliament should have the last word, and that Parliament is the one that has to face the electorate. The political choices that are made must be reasonable and cannot violate the Charter. I fully agree with your reasoning. This is not contrary to what the Supreme Court said. It may be an interpretation or a response to the rulings of the Supreme Court, but like laws, those rulings are subject to interpretation.
So, I am inclined to interpret it as giving precedence to Parliament's sovereignty, which is the very foundation of our democracy.