Jean-Francois Delisle said if elected, his party will negotiate with the provinces to reopen the Constitution in order to abolish the Senate.
He suggests the party could kill two birds with one stone by using the opportunity to deal with the niqab issue.
"Thomas Mulcair is ready to open the Constitution for the Senate, so why wouldn't he be ready to open it up on this issue?" Delisle asked during an interview with The Canadian Press at a cafe in Lac-Megantic, Que., on Friday.
Delisle doesn't hide his disagreement with the wearing of a niqab while swearing the oath of citizenship.
"To have one's face covered for a swearing-in ceremony, I'm not in agreement with that," said Delisle, who is seeking to win Megantic-L'Erable, the riding held by outgoing Conservative cabinet minister Christian Paradis.
"I'm comfortable saying that and I think my party is also comfortable saying that."
However, most NDP candidates in Quebec have been walking on eggshells compared to their Conservative and Bloc Quebecois counterparts, who have been categorically opposed to faces being covered during such ceremonies.
The Liberals have invoked the Charter of Rights and Freedoms in saying the wearing of niqabs at these events constitutes an individual right that the majority cannot deprive of minority groups.
Asked about the niqab issue in Saskatchewan on Friday, NDP Leader Tom Mulcair said the party would let the legal challenge drop if it forms the government and would respect the courts.
Delisle said freedom of religion as preached by the legislators of the day in the 1980s may have a different context today.
"Currently, there is a Charter of Rights and Freedoms," he said. "The charter then gives rights to people, and as a politician and as a legislator, if we want to change that, we have to change the Constitution."
He says radical movements have become more commonplace and it would be a shame if these types of groups were granted greater freedom than the majority.
Delisle accused the Conservatives of drumming up the niqab issue rather than discussing pertinent issues.
On Friday, the Bloc Quebecois released a video on YouTube suggesting a vote for the New Democrats is a vote in favour of pipelines and niqabs.
To that, Mulcair's spokesman Karl Belanger tweeted: "The National Front has entered the campaign," referring to France's far-right political party.
Earlier this week, the Federal Court of Appeal ruled that a federal ministerial directive forbidding Muslim women from wearing a niqab during ceremonies was invalid.
One day later, federal Immigration Minister Chris Alexander announced in a statement the government would seek leave to appeal the ruling before the Supreme Court of Canada.
On Friday, the Conservatives asked the courts to suspend the judgment while awaiting word from the high court.
The legal battle has been fought by an Ontario woman named Zunera Ishaq, 29, who wants to be allowed to wear a niqab while swearing the oath of citizenship.
Melanie Marquis, The Canadian Press
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