Not only is little known about how he was chosen, there's also no new candidate in sight.
Nadon's name was on a list of three potential candidates. That list of three, which had been drawn up by a selection committee made up of MPs, was then sent to the government. That means two other suitable candidates are presumably available to fill the empty Quebec seat on the top court. But it's not known who they are, or whether a new batch of candidates will be drawn up.
All that's certain is that the top court has been staffed by eight judges, not nine, since the end of August, and that it bears a heavy workload, including such nation-defining cases as the future of the Senate and physician-assisted suicide.
The top court ruled that Nadon, a Federal Court judge and native Quebecer who lives in Ottawa, couldn't fill the Quebec slot because he's not a sitting Quebec judge nor a current member of the Quebec bar.
Adam Dodeck, a lawyer and law professor, said in a phone interview that Nadon's appointment shows the system is broken.
"It hasn't delivered on what this government and previous governments promised Canadians, which is accountability and transparency in the Supreme Court selection process, and it's failed utterly in both respects."
An ad hoc committee of five MPs, bound by a confidentiality agreement, whittled down a list of nominees chosen by the government to three names. One of those names was Nadon's.
Secrecy was paramount
Françoise Boivin, the NDP MP on the committee, said secrecy was paramount. "It's so confidential that we couldn't keep any documents; we received things on USB keys that you had to return, and you had codes. It's a cone of silence type of thing."
The iron-clad clandestine process made it all the more puzzling when Prime Minister Stephen Harper said in the House of Commons on April 1, "During consultations, all of the parties in the House agreed with the idea of appointing a Quebecer from the Federal Court to the Supreme Court."
Harper then went further: "The Liberal Party in fact supported the nominee for the Supreme Court," he said.
Liberal justice critic Sean Casey has written a letter to the commissioner of federal judicial affairs asking for an investigation into Harper's comment.
Liberal MP Irwin Cotler has filed dozens of questions in Parliament, including a query about what consultations Harper was referring to and how did he find out about them. The government has 45 days to reply.
Boivin thinks Harper's comments might have been a trap to force committee members to end their vow of secrecy. "I know, I'm not born yesterday, as a lawyer I know exactly what they're trying to do," she said, in a telephone interview.
Did Harper breach confidentiality?
Harper is not himself breaking the confidentiality agreement, Boivin says. "How can he be breaking confidentiality when he's not part of the committee?"
Asked if someone else on the committee could have leaked details to Harper or his office, Boivin said nothing she's heard from Harper leads her to believe he has genuine knowledge of the proceedings. "It's empty words in my book, because he doesn't know."
Given that Harper has spoken about not just the results but the actual deliberations of the committee, it's possible Boivin and the other opposition MP on the panel — Liberal Dominic LeBlanc — could simply use their parliamentary privilege and spill the beans about how Nadon was chosen.
Legally, if the words are said in the House of Commons, parliamentary privilege is a powerful implement that bestows legal immunity from civil or criminal liability.
LeBlanc did not respond to a phone call about whether Harper's remarks would prompt him to break his confidentiality pledge.
Boivin says it would "kill her" to break the agreement. "I have a reputation as a lawyer, as a person of her word."
The three other MPs on the committee are Conservatives — Robert Goguen, Jacques Gourde and Shelly Glover.
Asked if the selection of one of the top judges in the country should be decided more transparently, Boivin said the process should be taken out of the hands of politicians. On the other hand, she also thinks the process worked extremely well when Justice Richard Wagner was chosen in 2012.
"I was so happy with it," she said, stipulating she could say no more.
Meanwhile, the Supreme Court has been operating with a vacancy for the past eight months and Justice Louis LeBel must retire by November, vacating another seat.