Mackeigan v Hickman

Mackeigan v Hickman, [1989] 2 S.C.R. 796 is a leading Supreme Court of Canada decision on judicial independence. The Court unanimously held that to require a federal judge to explain his or her decisions would violate the principle of judicial independence.
Background.
Donald Marshall was an Aboriginal youth who was wrongly convicted of murder in 1971. In 1983, the federal government, on the basis of new evidence, referred the case to the Nova Scotia Court of Appeal who overturned the conviction.
The panel which heard the reference included Justice Pace who was the Attorney General of Nova Scotia at the time of the investigation in 1971. At the end of the Court's judgement it was observed that Marshall was largely at fault for his own conviction by misleading the investigation and that "any miscarriage of justice was more apparent than real". This comment had a major effect on the amount of settlement Marshall received.
In 1986, the Nova Scotia government established a royal commission, under the "Public Inquiries Act", to investigate the handling of the Marshall case. As part of the investigation the Commission tried to compel the judges on the reference, including Pace, to testify. The judges applied for a declaration that the Commission had no authority to compel them as they were protected by judicial immunity.
The Supreme Court considered two issues:
The majority held that the judges could not be compelled and that the direction to the Commission was not "ultra vires" the province.
Reasons of the court.
Three reasons were written for the majority.
Justice McLachlin, writing for L'Heureux-Dubé and Gonthier, held that,