Just to help my education could you refrence your post? Are you a constitutional lawyer or in law school?
Law school, and it's very confusing stuff so I don't think anyone not paying thousands of dollars to be taught this stuff should feel bad for not understanding
Is there a book or an article about SC opinions vs rulings?
Not on that specifically, but if you're interested in this kind of thing (and have a chunk o money to spare) the best book is
Constitutional Law of Canada by Peter Hogg
For my understanding, based on your post - the basic idea is that the Gov can now legislate over marriage and if they choose to define marriage as 1 man & 1 woman will the SC overturn that if a gay couple brings a lawsuit?
Whatever law the Feds pass will be supported by the Supreme Court
What's the purpose of just getting an opinion then? To show the conservatives that they could be facing a lawsuit if they don't vote in favour?
As I understand it, the Federal Liberal gov't wants to pass a federal law legalizing gay marriage all across Canada, but a number of Provincial gov'ts oppose that and were arguing that it's the Provincial gov'ts that have the exclusive power to make laws regarding marriage.
Today the SCC said no, it's withing the power of the Federal gov't to make the law in this area.