OTTAWA -- The man who launched a legal challenge to Quebec's law on unilateral secession is posing some questions for Tom Mulcair that could prove awkward for the NDP leader.

Keith Henderson wants to know if an NDP government would continue to intervene in support of his court challenge to Bill 99, a 1999 provincial law which asserts that Quebecers alone have the right to democratically determine their own future, without interference from the rest of Canada.

He's also asking Mulcair to clarify if he believes aboriginal people and other "loyal Canadians" could separate from Quebec if the province were to secede from Canada and whether he believes an independent Quebec would have to pay for its share of the federal debt and compensation for federal assets in the province.

Henderson and other members of an advocacy group he chairs, the Special Committee for Canadian Unity, held a news conference Tuesday to put these and six other questions to Mulcair, all aimed at pushing him to clarify the NDP's policy on Quebec secession.

The committee's move came just two days before the first French televised leaders' debate of the marathon federal election campaign.

The NDP's policy on Quebec secession is "in absolute defiance of the terms of the Constitution of Canada," said committee member Stephen Scott, a retired constitutional law professor.

The committee's objective is to stop the NDP from feeding steak to the separatist tiger, Scott added, with a policy that amounts to acceptance of unilateral secession.

At issue is the NDP's unity bill, proposed in 2013 as a replacement for the existing Clarity Act, which sets out the conditions under which the federal government would agree to negotiate secession.

The Clarity Act was based on the advice of the Supreme Court of Canada, which ruled in 1998 that Quebec has no legal right to unilaterally secede from Canada on its own terms. Rather, the top court said secession could only be accomplished legally through negotiation of a constitutional amendment that would involve all manner of explosive issues, including the province's borders and the division of assets and liabilities.

In response to the Clarity Act, Quebec's then-separatist government passed Bill 99, which asserts that "the Quebec nation has the right to democratically decide its own future."

That central premise is repeated, word for word, in the NDP's proposed unity bill, Henderson's committee noted.

The NDP bill also adopts the same threshold for a successful referendum on secession: a bare majority vote of 50 per cent plus one.

By contrast, the Clarity Act declares that there is no right to unilateral secession and specifies that a constitutional amendment would be required. It also specifies that a clear majority vote on a clear question would be required to trigger negotiations, which would have to address the division of assets and liabilities, the rights and territorial claims of aboriginal peoples, the protection of minority rights and any changes to the province's borders.

Henderson's committee questioned why the NDP's unity bill drops all reference to negotiations on Quebec's borders or the division of assets and liabilities.

"Do you accept that secession is a matter for the Canadian people as a whole; that the Canadian people through their institutions can say Yes or No to secession and, if they do say Yes, they can do so on any terms and conditions they please, including to the boundaries of Quebec?" the committee asks Mulcair in one of its nine questions.

The committee called on Mulcair to abandon plans to introduce the unity bill and to leave the Clarity Act in place. It also called on him to continue the federal government's intervention in Henderson's legal challenge to the constitutionality of Bill 99.

Stephen Harper's Conservative government decided to intervene two years ago. At the time, Mulcair criticized the government, arguing that it was unnecessarily reviving a dormant constitutional debate that would only wind up giving new life to the sovereigntist movement.

During the election campaign, Mulcair has similarly accused Liberal Leader Justin Trudeau of trying to reignite "old quarrels" with his criticism of the NDP's acceptance of 50 per cent plus one vote as sufficient to trigger talks on Quebec secession.

"Quebec is never more than one election away from the risk of a referendum," Henderson's committee countered.

"These are not old quarrels ... Separatism is very much alive."