OTTAWA -- Everything from the parsing of verb tenses to the intentions of the framers of the failed Meech Lake constitutional accord was tossed into the hopper Wednesday as lawyers argued over the composition of the Supreme Court of Canada.

The legal battle over Prime Minister Stephen Harper's sixth appointment to the top court only occasionally touched upon the credentials of Justice Marc Nadon, the man at the centre of the unprecedented dispute.

Nadon, 64 and semi-retired from the Federal Court of Appeal before he was plucked from obscurity last September, faces a constitutional challenge because he may not meet the criteria to sit as one of the three Quebec-based judges that are required on the nine-member bench.

In its haste to legitimize the appointment last fall, the government altered the Supreme Court Act in an omnibus budget bill to "clarify" the criteria for Quebec appointees.

The remaining Supreme Court justices -- seven are hearing the Nadon reference -- have been asked to determine whether Federal Court judges are excluded from the Quebec spots, according to the wording in the legislation, and also whether Parliament has the power to unilaterally rewrite that legislation.

The court heard that while the first question arguably balances on a parsing of the fine print, the latter is foundational to the rule of law in a constitutional democracy.

"Who can sit on the court is a fundamental characteristic of the court," argued Patrick Monahan, the deputy attorney general of Ontario and noted legal scholar.

"If the Parliament of Canada wishes to amend or alter the qualifications of who comes from Quebec, it can only do so through means of a constitutional amendment."

While the court was hearing five hours of dry legal argument, Justice Minister Peter MacKay was making his own case before the news cameras at an event in west-end Ottawa.

He said it would be unfair to exclude Federal Court judges from Quebec, while judges from other provinces don't face similar restrictions.

"Federal Court judges who come from the province of Quebec should enjoy the same rights and privileges for consideration for Supreme Court appointment as every other province," MacKay said.

"This is a fundamental issue of fairness.... There's really nothing more critical to the administration of justice than the perception, the reality of fairness."

The problem is the language in the Supreme Court Act clearly lists which Quebec courts can be used as feeders for Supreme Court appointees, as well as citing lawyers with 10 years in the Quebec bar association.

Whether Nadon qualifies may hinge on how his Supreme Court peers interpret that 10-year membership on the Quebec bar.

Rocco Galati, the constitutional lawyer who sparked the initial challenge to Nadon's appointment last fall, said the rules are the rules -- and there's no "constitutional imperative ... that every single lawyer in the country should have a fair crack at sitting up there," on the top bench.

"It's not about the person's right to be up there," Galati told the justices. "It's about the constitutional requirements to maintain the federalism that was brokered between the provinces and the federal government."

The seven sitting justices were highly engaged in the hearings, grilling federal government lawyer Rene LeBlanc in particular.

LeBlanc argued that the during negotiations on the Meech Lake constitutional accord in the late 1980s, annotations on the pages show the Quebec government agreed to Federal Court judges being eligible as provincial appointees to the top court. The accord ultimately failed, however, when Newfoundland and Manitoba didn't sign on.

"What happened since 1992 that today the appointment of a Quebecois judge from the Federal Court is so problematic and seems to threaten the very objective of preserving civil law within the court?" the federal lawyer asked.

"In fact, if we followed Quebec's suggestion, then we would end up excluding many candidates who would be well qualified to fill a position on the Supreme Court bench."

Lawyer Andre Fauteux, representing the Quebec government, argued it was a compromise in 1875 that led to the creation of the Supreme Court with two of seven judges from Quebec (subsequently changed to three of nine in 1949).

He said if those rules can be unilaterally rewritten by the federal government or any single province, "then I think we will have effectively eliminated a huge stretch of history regarding the Canadian constitution."

The federal proposal, said Fauteux, is "absolutely, unequivocally unacceptable for Quebec."

As is usual, the Supreme Court justices reserved judgment and gave no time frame for when a ruling on the reference would be released.