What is the mootness doctrine and what is the effect of mootness on constitutional issues?

[60] The third rationale underlying the mootness doctrine is the need for the court to demonstrate an awareness of its proper law-making function. As enunciated by Justice Sopinka, this facet of the doctrine is concerned with unwarranted intrusions by the adjudicative branch of our political system into the legislative sphere. This consideration is less applicable within the factual context of this case than it is in other circumstances. In Borowski v. Attorney General for Canada, supra, the issues were constitutional in nature and involved challenges to the validity of legislation on the grounds that it violated the Canadian Charter of Rights and Freedoms. A conclusion that the legislation was unconstitutional would of necessity involve an intrusion into the parliamentary domain, as the offending statutes would have to be struck down or amended by the courts to conform with the Charter. In the present case, the issues involve the interpretation of existing legislation rather than a pronouncement on the statute’s constitutional validity and the amendments that might entail. The interpretation of legislation is a function that has traditionally been performed by the courts.