33. (1) Parliament or the legislature of a province may expressly declare in an Act of Parliament or of the legislature, as the case may be, that the Act or a provision thereof shall operate notwithstanding a provision included in section 2 or sections 7 to 15 of this Charter.
Section 33 of the Charter of Rights and Freedoms is commonly referred to as the “notwithstanding clause.” Its function is to prevent a court from invalidating a law that violates Charter provisions relating to fundamental freedoms (section 2), legal rights (sections 7-14), or equality rights (section 15).
Provincial or federal governments can use section 33 when they want to pre-emptively shield a law from judicial invalidation on these specific grounds, or when they want to revive a law that has already been invalidated by a court on these grounds. While an invocation of section 33 expires after five years (as per section 33(3)), there is no limit on the number of times that the clause can be reused for a given law (section 33(4)).
Crucially, section 33 cannot be used to shield a law from invalidation on the grounds that it violates democratic rights, mobility rights, or minority language rights under the Charter. It also can't be used to shield a law from invalidation on the grounds that it violates the Aboriginal and Treaty rights that are "recognized and affirmed" by section 35 of the Constitution Act, 1982.
When the Charter was being drafted, federal and provincial leaders were divided on whether it should contain a notwithstanding clause. For the most part, the clause's proponents (such as the premiers of Saskatchewan and Alberta) argued that it was a democratic backstop that would prevent unelected judges from holding too much power vis-à-vis the interpretation and enforcement of the Charter. By contrast, those opposed, including then Prime Minister Pierre Elliott Trudeau, thought that the clause could undermine the Charter by letting legislatures ride roughshod over rights. In the end, Trudeau was forced to compromise on the notwithstanding clause to ensure that the Charter was passed with the support of most provinces (all except Quebec).
The notwithstanding clause has never been used by most provinces, nor by the federal government. It has, however, been used by Quebec, Saskatchewan, Alberta, and, most recently, Ontario. Here are a few well-known examples:
Quebec
Saskatchewan
Ontario