Today the right to effective assistance of counsel extends to all accused persons.  In Canada that right is seen as a principle of fundamental justice.  It is derived from the evolution of the common law, s.650(3) of the Criminal Code of Canada and sections 7 and 11(d) of the Canadian Charter of Rights and Freedoms.

Where counsel fails to provide effective representation, the fairness of the trial, measured both by reference to the reliability of the verdict and the adjudicative fairness of the process used to arrive at the verdict, suffers.  In some cases the result will be a miscarriage of justice. 

To succeed in setting aside a trial verdict on the basis of the ineffective assistance of counsel, the appellant must show two things:

1.       That counsel’s acts or omissions constituted incompetence

Incompetence is determined by a reasonableness standard.  The analysis proceeds upon a strong presumption that counsel’s conduct fell within the wide range of reasonable professional assistance.  The onus is on the appellant to establish the acts or omissions of counsel that are alleged not to have been the result of reasonable professional judgment.  The wisdom of hindsight has no place in this assessment.

R. v. G.D.B., 2000 SCC 22 (CanLII) at para 27

Where, in the course of a trial, counsel makes a decision in good faith and in the best interests of his client, a court should not look behind it save only to prevent a miscarriage of justice:

Supra, at para 34

2.       That a miscarriage of justice resulted

 Miscarriages of justice may take many forms in this context.  In some instances, counsel’s performance may have resulted in procedural unfairness.  In others, the reliability of the trial’s result may have been compromised. In those cases where it is apparent that no prejudice has occurred, it will usually be undesirable for appellate courts to consider the performance component of the analysis. This can be left to the legal profession’s self-governing body.

Supra, at para 28