QUEBEC -- The parties in Quebec's legislature all voted in favour of a motion Wednesday to denounce the federal government's court challenge of a 13-year-old provincial law known as Bill 99 on the rules for Quebec sovereignty.

The legislature called on Prime Minister Stephen Harper's government to withdraw its participation in a legal challenge, filed in Quebec Superior Court last week.

The motion tabled by Premier Pauline Marois "condemns the intrusion by the Government of Canada into Quebec democracy."

While the vote was unanimous, there were varying levels of optimism for the motion from different parties. The Liberals, who voted against the PQ's Bill 99 when it was proposed in 2000, gave Wednesday's motion tepid support.

Last week, the federal government intervened in a court case brought by two Quebecers which challenged Bill 99, which sets the bar to achieve sovereignty at a simple 50-per-cent-plus-one majority.

The Quebec law, passed by the PQ government of then-premier Lucien Bouchard, was a challenge to the Clarity Act brought in by Ottawa in the wake of the razor-thin federalist win in the 1995 Quebec referendum. It sets its own rules for Quebec independence.

The Liberals warned at the time that the bill would be struck down in court. A court case against Bill 99 was filed in 2000 and it has advanced at a snail's pace since then.

Before the motion was presented in the legislature, Quebec Intergovernmental Affairs Minister Alexandre Cloutier insisted that Ottawa's intervention in the case "is a disturbing assault on Quebecers' freedom of political expression."

The Liberals' Pierre Moreau said his party's support for the motion should only be seen as reaffirmation of the belief that only the national assembly has the power to determine conditions for a referendum on Quebec's political or constitutional future.

And that's where his agreement with the PQ ended. Moreau went on to argue that the entire dispute with the federal government stemmed from the fact that both times the PQ held an independence vote, in 1980 and 1995, the questions were lengthy and unclear.

Moreau said that while his party supports the principle of 50-per-cent-plus-one, it also demands a clear question such as: "Do you want Quebec to be an independent country?"

"The federal Clarity Act and Bill 99 are the direct result of the vague and ambiguous statements in the questions from the two referendums," Morneau said.

"The current premier likes to talk about the Scottish example. She should turn red with shame if she tried seriously to compare the wording of the question put to Quebecers compared to the one the Scots will be responding to."

Academic research has pointed out, consistently, that the way an independence question is worded can have a huge influence on a referendum result.

In Scotland, voters will be asked next September: "Should Scotland be an independent country?"

In 1995, Quebecers were asked: "Do you agree that Quebec should become sovereign, after having made a formal offer to Canada for a new economic and political partnership, within the scope of the bill respecting the future of Quebec and of the agreement signed on June 12, 1995? Yes/No."

That was far shorter than the question put to Quebecers in 1980 -- which was nearly triple the length at 116 words.

The federal government is remaining tight-lipped on the case.

The senior minister for Quebec, Denis Lebel, had been conducting interviews on it earlier in the week where he appeared to contradict the federal position and suggest a vote of 50 per cent plus one was enough to break up the country.

On Wednesday, his office issued a statement: "The federal government did not initiate these proceedings. No one wants another referendum. It is completely normal for the federal government to defend Canadian law. As this case is before the courts, we will make no further comment."