The legal arguments over the constitutionality of Canada's Royal baby bill didn't end when it became law in March. In fact, they're heating up just as Prime Minister Stephen Harper arrives in London to meet the Queen.

Last Friday, Justice Minister Rob Nicholson was served notice of a Quebec court challenge to the law Parliament passed to agree with British rule changes for the Royal line of succession.

A group of legal scholars and Constitutional experts from Quebec consulted with like-minded lawyers, academics and monarchy experts from across Canada to prepare the motion, filed in Quebec Superior Court.

What if Will and Kate have a girl?

When the Duchess of Cambridge delivers her baby – due next month – it will follow Prince William in the line of succession, regardless of where things stand with implementing these reforms.

All 16 countries that have Queen Elizabeth as head of state must finish their own legislative processes before the changes are final. But the rules will apply as of the date when the Commonwealth leaders first agreed to the move: Oct. 2011.

Even if the baby is a girl and a little brother follows, this first-born child will remain ahead in line.

The challenge is not an objection to changing the rules around who can become king or queen. Instead, the group says it objects strongly to the manner in which the federal government chose to change those rules.

"We need to set the right precedent," says André Binette, the lawyer acting as spokesman for the challenge, adding that it's a "mystery to me" why no province objected to what he sees as a deliberate federal strategy to avoid the established process for amending the Constitution, despite provinces' sovereign relationship with Canada's Crown.

"The question is, has patriation of our Constitution really been completed?" Binette says, suggesting that if the 1982 rules for amending the Constitution don't apply to these reforms to the monarchy, in the future the federal government could seek to act unilaterally in other areas.

Binette admits that Canadians were "bored to tears" by the Meech Lake Constitutional negotiations, at first. "But then it almost broke up the country."

Now, as then, once the underlying issue is explained to the public they'll feel differently, Binette says.

Nicholson may skip lower court

The federal government now has 30 days to respond, and the Justice department confirms it will "defend Parliament's legislation."

When asked about the pending challenge Monday, Nicholson stuck to the Harper government's position that no Constitutional amendment is necessary.

"We’re on solid ground on this. We’ve had excellent advice on this," he told reporters.

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But rather than defend the Constitutionality of its legislation before a Quebec Superior Court judge first, Nicholson may opt to refer arguments straight to the Supreme Court for one definitive ruling.

If he takes that route, it will be telling, Binette says, adding that "I can't see our Supreme Court choosing [the federal government's argument]."

Allowing the process to wind its way through the lower court first could take several years, putting Canada's support of the changes — which include allowing first-born children of either gender to inherit the throne, regardless of the gender of their younger siblings — in limbo long past the time when the 16 countries who have Queen Elizabeth as their monarch may have hoped to have the reforms take effect.

Challenge doesn't 'contest political decision'

The court challenge is a "public interest action" that carries the name of two legal scholars from Laval University: Geneviève Motard and Patrick Taillon.

It is not affiliated with the Quebec government. The group that prepared it are "volunteers" who represent a broad spectrum of political views in Quebec: some sovereigntist, some federalist, some supportive of the monarchy and others with more republican views.

"The aim of the present motion is not to contest the political decision to amend the rules … but rather to ensure that such amendments are made in compliance with the Constitution," the court document says.

In the motion submitted on Friday, the group argues that section 41 of the Constitution requires the federal government to obtain the unanimous consent of all provincial legislative assemblies for any changes to "the office of the Queen."

The federal government argues it isn't changing the office of the Queen with this law. But that interpretation is too narrow, Binette believes. "To me, the office can't be seen to be separate from the rules around the office-holder."

Nevertheless, no consent was sought before the Royal baby bill became law. In fact, provinces were not even consulted through informal means.

When asked about this on the day the bill was first introduced, Heritage Minister James Moore, speaking for the government, said the provinces knew well in advance that the Harper government intended to introduce a bill to follow through on the agreement made at the Commonwealth Heads of Government meeting in Perth, Australia, in October 2011.

No province had voiced any objection to the changes discussed, Moore said, implying that the federal government equated this lack of objection with approval.

New Zealand, Australian approach different

"The bill that we introduced into Parliament received the unanimous consent of everybody – the NDP, the Liberals, the Bloc, everybody," Nicholson said Monday. "It’s now the law of this country and that's certainly consistent with all other Commonwealth countries who have the Queen as head of state have done."

In fact, Canada was the first to pass the changes in its Parliament. The U.K. legislation to which Canada's law assented only passed in late April – a month after Canada's bill received Royal Assent.

Many of the smaller countries involved are not passing legislation to implement the reforms. But two other comparable countries are: New Zealand has just tabled its legislation, while Australia is not only passing federal legislation but having each of its state governments approve of the bill as well, to recognize the sovereign jurisdiction of Australian states and their own unique relationship to the Crown.

Australia is similar to Canada's federal situation, the Quebec scholars argue. But Canada did not pursue a process that would have seen each province give its consent.

Further, Canada did not draft its own language to amend the ancient Acts that needed to be reformed to modernize the monarchy. The Canadian law simply notes the British law and expresses its agreement.

"Simply consenting to a foreign law presents serious Constitutional issues," Binette says, pointing out that the Supreme Court's 1981 reference case on the patriation of the Constitution found that the ancient Acts being modernized with these reforms are not just British laws but also Canadian legislation.

Australia and New Zealand's approach agrees with this more nationalistic interpretation. They are not assenting to the British law, but passing their own amendments as sovereign countries whose systems of government have evolved from the same origins.

Bad precedent for future reforms?

Binette says the precedent is especially important because Prince Charles has spoken about the possibility of more changes when he becomes king. If a bad precedent is allowed to stand, provinces may be ignored again in the future.

The court challenge also argues that another aspect of the reforms — which removes the ban on a future monarch marrying a Roman Catholic, but still requires the monarch to be Anglican — violates the principle of religious freedom. Individuals of other faiths are still barred from the Throne, something Binette characterizes as religious discrimination "shocking" in its incompatibility with the Charter of Rights and Freedoms.

The motion also argues all Canadian laws must be in both English and French . But the U.K. law was written only in English, so Canada has, they argue, failed to maintain the requirement to legislate in both official languages by assenting to the British Act.

"They could have at least annexed the U.K. law in French," Binette says.

Binette believes several possibilities could result from a successful challenge. Most simply, the federal government could be ordered to go back and seek the provinces' consent.

But a bigger can of worms could also open, Binette thinks. Should the federal government lose this case or its Senate reform reference case (or both) at the Supreme Court, the negotiations with the provinces to amend the Constitution that may follow could be "unpredictable."

Abolishing the monarchy in Quebec or across Canada could become part of those discussions, Binette says.

Read the motion for judgment filed Friday: