Quebec's legislative initiative is problematic because assisted suicide is a criminal offence in Canada. The provinces have no authority to amend the Criminal Code. But they do have authority to regulate healthcare. Quebec's legislation is almost certainly intra vires. End-of-life care has what Canadian courts call a "double aspect": it falls under provincial healthcare jurisdiction and under federal criminal jurisdiction. Recourse to the "double aspect" concept arises because Canada's constitution enumerates the powers of both the federal and provincial authorities.
When federal and provincial regulation clash, federal legislation prevails: the doctrine of paramountcy. Does Quebec's new law clash with the federal prohibition on assisted suicide? It surely undermines the purpose of the criminal prohibition. I imagine that any court seized of the matter would conclude that Quebec can pass "right to die" legislation but that it must yield to federal criminal law. Doctors and others who help euthanize patients would be subject to criminal sanctions regardless of the right enshrined in provincial law. For more, see this post by Daniel Weinstock.
But there is a problem: prosecutorial discretion. Indeed, the expert report commissioned by the Quebec government on implementing assisted suicide legislation suggested that Quebec issue guidelines to prosecutors, using its authority over administration of justice. Regrettably -- because this would at least have made clear to all concerned what is really going on -- Quebec has opted not to do so, leaving it up to prosecutors to deduce from the new legislation that they should not pursue assisted-suicide charges. It is, in short, a matter of their discretion.
The difficulty this raises is that prosecutorial discretion is virtually unreviewable. Here is what the Supreme Court of Canada said today, in reasons written by Moldaver J.:
 The many decisions that Crown prosecutors are called upon to make in the exercise of their prosecutorial discretion must not be subjected to routine second-guessing by the courts. The courts have long recognized that decisions involving prosecutorial discretion are unlike other decisions made by the executive....Judicial non-interference with prosecutorial discretion has been referred to as a “matter of principle based on the doctrine of separation of powers as well as a matter of policy founded on the efficiency of the system of criminal justice” which also recognizes that prosecutorial discretion is “especially ill-suited to judicial review”... (cites omitted)
 Manifestly, prosecutorial discretion is entitled to considerable deference. It is not, however, immune from all judicial oversight. This Court has repeatedly affirmed that prosecutorial discretion is reviewable [solely] for abuse of process...
 Regardless of the precise language used, the key point is this: abuse of process refers to Crown conduct that is egregious and seriously compromises trial fairness and/or the integrity of the justice system.Even if a court declared that the criminal prohibition on assisted suicide is paramount over provincial legislation, how would anyone ever know that prosecutors did not rely on Quebec's "right to die"in deciding not to prosecute? It gets messier once one considers the possibility of guidelines. The following passage may inspire Quebec to issue some after all:
What goes for Charter scrutiny here should also go for general constitutional scrutiny. On Moldaver J.'s logic, Quebec could issue guidelines advising prosecutors not to pursue assisted suicide charges and no court could declare the guidelines unlawful! Finally, I note that the content of a Crown policy or guideline may be relevant when a court is considering a challenge to the exercise of prosecutorial discretion. Policy statements or guidelines are capable of informing the debate as to whether a Crown prosecutor’s conduct was appropriate in the particular circumstances. See R. J. Frater, Prosecutorial Misconduct (2009), at p. 259. For example, a decision by a Crown prosecutor that appears to contravene a Crown policy or guideline may provide some evidence that assists the claimant in establishing the threshold evidentiary foundation. However, as the intervener the Director of Public Prosecutions of Canada submits, Crown policies and guidelines do not have the force of law, and cannot themselves be subjected to Charter scrutiny in the abstract... Emphasis added.
But that is not all. Moldaver J. had to address an argument that prosecutors had to take into account Anderson's aboriginal status in deciding to bring charges, as a matter of constitutional right. He noted that prosecutors sometimes have constitutional obligations:
Perhaps, then, a declaration that federal criminal law is paramount over Quebec's assisted suicide legislation would impose a constitutional obligation on prosecutors regardless of any provincial statute or guidelines. But would this mean that prosecutors have no discretion at all? Would they be bound to bring charges? It would presumably amount only to a mandatory consideration, but proving -- one way or the other -- that they gave it appropriate weight would arguably be beyond the scope of judicial review. In sum, prosecutorial discretion applies to a wide range of prosecutorial decision making. That said, care must be taken to distinguish matters of prosecutorial discretion from constitutional obligations. The distinction between prosecutorial discretion and the constitutional obligations of the Crown was made in Krieger, where the prosecutor’s duty to disclose relevant evidence to the accused was at issue:In Stinchcombe, supra, the Court held that the Crown has an obligation to disclose all relevant information to the defence. While the Crown Attorney retains the discretion not to disclose irrelevant information, disclosure of relevant evidence is not, therefore, a matter of prosecutorial discretion but, rather, is a prosecutorial duty. [Emphasis added; para. 54.]Manifestly, the Crown possesses no discretion to breach the Charter rights of an accused. In other words, prosecutorial discretion provides no shield to a Crown prosecutor who has failed to fulfill his or her constitutional obligations such as the duty to provide proper disclosure to the defence.
All this may be mooted if the Supreme Court strikes down the assisted suicide prohibitions, as they may well do, but it is a very thorny problem.