There are several ways the Supreme Court of Canada influences and shapes the legal status and application of the constitution of Canada. Primary among those, however, is its power of judicial review.
Early in Canadian history, federal courts were limited in their ability to nullify statute laws that violated organic law. This is similar to the British experience; with a sovereign parliament, laws cannot be "unconstitutional," because any decision taken by Parliament is—by its very nature—constitutional. However, the introduction of the Charter of Rights and Freedoms, in 1982, extended, for the first time, an absolute power of negative lawmaking to the federal courts, similar to that which was self-assumed by the United States Supreme Court in its 1803 ruling in Marbury v Madison.
The Canadian Supreme Court, since 1982, has enjoyed the authority and obligation to restrain the enforcement and application of laws if they violate the basic constitutional protections extended to Canadians by the charter. In its role as guarantor of the charter, above all others, the Supreme Court is central to shaping the Canadian constitutional experience.