We found out the answer to that in one of the most important early cases interpreting Canada’s new-as-of-1982 Canadian Charter of Rights of Freedoms in a case that has to be in consideration for the title of worst reasoned Charter decision of all time. In Reference Re Motor Vehicle Act  2 S.C.R 486. the Court had its first opportunity to resolve the most crucial question about the interpretation of Section 7 of the Charter, which reads as follows:
7. Everyone has the right to life, liberty and security of the person and the right not to be deprived thereof except in accordance with the principles of fundamental justice.If you're an American, does that look familiar? The Fifth Amendment provides that no person shall "be deprived of life, liberty, or property, without due process of law". Now there is a vast jurisprudence and scholarly literature concerning the appropriate scope of the Fifth and Fourteenth Amendments, with a particularly notable debate about the appropriateness of "substantive due process", a doctrine which has animated such notable American decisions as Lochner and Roe v. Wade.
Now the language in the two jurisdictions is not identical, but the similarities suggest that the SCC might at least have referred to the American experience to help it understand the immense implications of the choice of interpretation they were about to make.
The Court didn't see it that way. The majority opinion, written by Lamer J. entirely rejected the idea of consulting American law, rejecting
the characterization of the issue in a narrow and restrictive fashion, i.e., whether the term "principles of fundamental justice" has a substantive or merely procedural content. In my view, the characterization of the issue in such fashion preempts an open-minded approach to determining the meaning of "principles of fundamental justice".Got that? Substantive Due Process and Procedural Due Process are (Gasp!) "American concepts". Not only don't we care how the Yanks reason about things, but we're not even going to let our reasoning be tainted by use of these foreign concepts.
18. The substantive/procedural dichotomy narrows the issue almost to an all or nothing proposition. Moreover, it is largely bound up in the American experience with substantive and procedural due process. It imports into the Canadian context American concepts, terminology and jurisprudence, all of which are inextricably linked to problems concerning the nature and legitimacy of adjudication under the U.S. Constitution.
Needless to say, after rejecting this distinction the Court went on to affirm full substantive due process, without using the barbarian words. Oh, and this was by the way the case which also at one stroke killed the doctrine of originalism in Charter jurisprudence. More is known about the original intent of Section 7 than about any other part of the Charter. The words "due process" were specifically avoided to prevent the possibility of the importation of American substantive due process to Canada. The words "fundamental justice" were intended to mean no more than procedural "natural justice". Lamer J. ignored the indisputable evidence of this intent, considering it to be "of little weight".
So if the Americans follow the advice of Dean Koh and other transnationalists and start using Canadian experience to help interpret their Constitution, don't expect Canada to be returning the favour.