Because of those leaks, he said during question period in the House of Commons on Wednesday, the government would "proceed with caution in the future" about allowing a committee of MPs to have an advance look at names of judges or lawyers being considered to fill vacancies on the court.
MacKay may have used the term "leaking" to refer to media reports that said the original long list of names chosen by the government and shown to the committee contained those of four Federal Court judges. Reports also said the shorter list chosen by the committee contained the names of two Federal Court judges, including Nadon's.
MacKay was responding to a question from Liberal Leader Justin Trudeau, who reminded MacKay the Conservatives had made an electoral promise that parliamentarians would be consulted in the choosing of new Supreme Court justices.
Trudeau asked whether those consultations would happen when a replacement is chosen for Supreme Court Justice Louis LeBel who has announced his retirement.
MPs bypassed in selection of Clément Gascon
Trudeau's question was pertinent because parliamentary consultation was bypassed in the selection of Justice Clément Gascon whose Supreme Court appointment was announced Tuesday.
The government has said it skipped the selection committee due to the need for speed considering the highest court has been operating with eight judges rather than nine since last spring.
In April 2013, Justice Morris Fish retired and in October Nadon was named to take his place.
In the process of choosing Nadon, a committee of five MPs — three Conservatives as well as one Liberal and one NDP member — studied several potential candidates last summer. The committee's job was to work from long list of names provided by the government and choose a short list of three.
From the short list the government selected Nadon.
But Nadon's appointment was challenged by a Toronto lawyer because he is a Federal Court judge and not a current Quebec lawyer nor a Quebec superior or appeals court judge. In March, the Supreme Court rejected the notion of the Federal Court judge representing Quebec on its bench, scotching Nadon's appointment.
None of the media reports that revealed names of candidates known by the committee indicated where the information originated.
Sworn to secrecy
The MPs on the selection committee were sworn to secrecy about their deliberations and how they voted when creating the short list of names. Documents handed out about the candidates were on USB keys that had to be returned.
But after Nadon's nomination was rejected, it seemed both MacKay and Prime Minister Stephen Harper skirted close to breaching the secrecy of the selection process.
On April 1 in the House of Commons, the prime minister said, "The Liberal Party, in fact, supported the nominee for the Supreme Court," which might have been a reference to Liberal MP Dominic LeBlanc, who was a member of the selection committee.
In question period on May 27, MacKay talked about "members of the parliamentary committee, including the honourable member who just spoke, the justice critic for the NDP party, who, it is now well known, would have seen the list and recommended the list that went forward that contained names of Federal Court judges from Quebec."
MacKay was referring to NDP justice critic Françoise Boivin. Boivin would certainly have seen the list, but has never said whether she agreed to recommend the short list containing Nadon's name.
The vacancy on the top court created by LeBel's retirement will open up in November. Mackay promised consultations with the Quebec legal community about replacing him, but has notsaid whether MPs will have a say.