Galati is the lawyer who successfully challenged Prime Minister Stephen Harper's appointment of Federal Court of Appeal Justice Marc Nadon to the Supreme Court of Canada.
This time Galati objects to the appointment of Mainville, a Federal Court of Appeal justice, to the Quebec Court of Appeal.
He alleges the government's goal in making this judicial shuffle is to ensure Mainville would be eligible for appointment to the Supreme Court of Canada when Justice Louis LeBel retires at the end of November.
On Monday Galati went to court to formally challenge the appointment, basing his argument on section 98 of the Constitution, which states, "the judges of the Courts of Quebec shall be selected from the bar of that province."
Mainville, who is an expert in aboriginal law, worked as a lawyer in Quebec for decades but ceased to be a member of the bar when he was appointed to the Federal Court in 2009.
The thing is, it doesn't appear anyone has been paying attention to section 98 for, well, a really long time.
Practice is key
A number of constitutional experts point to section 3(b)(ii) of the Judges Act, which states that anyone who has been a lawyer and then performed duties and functions "of a judicial nature" would be eligible for an appointment to a superior court.
And even though there is a hierarchy to Canada's laws where the Constitution reigns supreme, practice is key.
The federal government has for years been appointing provincial court judges to superior courts and courts of appeal without asking them to first go back to practicing law in their home province for a spell.
Pierre Thibault, assistant dean of University of Ottawa's civil law section says if one takes s. 98 literally, "two-thirds of the judges of the Quebec Court of Appeal would have been appointed illegally."
In the Nadon reference, the Canadian Association of Provincial Court Judges submitted a factum that highlighted a number of current examples.
"The current chief justice of the Court of Appeal of Manitoba was directly appointed to the Court of Appeal from the provincial court. The same is true of two current judges of the Quebec Court of Appeal as well as one judge of the courts of appeal of each of Ontario, Alberta and British Columbia. Moreover, one current member of the Supreme Court of Canada began her judicial career as a provincial court judge."
Would Galati even have standing?
Then there's standing — or the stake — an individual has in a particular legal question. Legal observers agree Galati clearly had standing in the Nadon case because the Supreme Court of Canada is the highest court of the land and has jurisdiction across the country.
Université de Montréal law professor and constitutional expert Stéphane Beaulac says it is not entirely clear what standing a Toronto lawyer would have in the appointment of a judge to the Quebec Court of Appeal.
Beaulac says Galati could craft an argument around his concern for the integrity of judicial appointments. Ultimately though, Beaulac says Galati would probably require someone in Quebec to join his challenge.
That though, might be harder than it sounds. Unlike Nadon, Quebec's legal community holds Mainville in high regard and has so far strongly endorsed the appointment.
"So in the public, in the public relations battle, Galati has a much harder case to make," said Beaulac.
"I don't think there is a chance that he will succeed."