Prior to 1982, the Canadian Constitution was based on the 1867 UK Statute the British North America Act. Pierre Trudeau, when he was Prime Minister, resolved to repatriate the Constitution, so we would no longer have a Constitution based on a statute passed in the UK Parliament.
That, of course, meant negotiations with the provinces. Malcolm Muggeridge once (accurately) described the Canadian provinces as “ten little tinpot Kingdoms”. As part of the negotiations, two of the provinces, Quebec and Alberta, pathologically jealous of their areas of jurisdiction granted them by the Constitution, insisted on the including of a so-called “notwithstanding clause” in the Constitution. Likely this was done to protect Alberta’s interests in the energy sector (the oilpatch) and Quebec’s linguistic interests (protection of the French language).
What this means, is essentially, a way for any provincial legislature to overturn a law, that it sees fit to do so.
So, for example, if Quebec passes language legislation that removes the rights of English-speakers in Quebec, and the Supreme Court of Canada declares that law unconstitutional, the Quebec provincial legislature (the National Assembly) can simply re-pass the law, invoking the notwithstanding clause. That re-instates the law, notwithstanding the judgement of the Supreme Court, for a period of 5 years.
What makes matters only worse is that civil rights are in the domain of the provinces – your civil rights can vary depending on which province you happen to reside in. (I still have trouble wrapping my head around this one.)
Originally, it was anticipated that the use of the notwithstanding clause would be very rare; the idea behind the 5 year limitation was that it was thought that voters would be so offended by the use of the notwithstanding clause, that they would throw-out the government that invoked it.
Needless to say, this has not been the case. In Alberta, where the oilpatch is concerned, or Quebec, where language is concerned, the notwithstanding clause will be re-invoked time and again, making the idea of Constitutional rights a joke. (They are a joke, when as George Carlin said, they’re not rights if anyone can just take them away, anytime.)