OTTAWA — If there is a national ground zero for our election campaign’s sudden fixation with the niqab and citizenship ceremonies, it is in Quebec where, on Friday night, the men who hope to be prime minister after Oct. 19 gathered for their final debate of the campaign.

This is the province where the central issue of the last provincial election, in 2014, was the so-called “Charter of Values”, a document presented by the incumbent premier Pauline Marois that, among other things, would have made it mandatory to have one’s face uncovered when providing or receiving a provincial service.

Marois and her separatist Parti Quebecois got thumped in that election while Quebec Liberal leader Philippe Couillard won big, partly because he rejected the extremes of the Charter.

Here we are nearly 18 months later and Stephen Harper’s Conservatives are campaigning that, if they are re-elected, they would pass a law requiring all who would take the oath of citizenship to show their faces during their swearing-in ceremony. Since 2011, 600,000 such ceremonies have taken place and there have been precisely two instances where a Muslim woman has declined to remove her face covering — the niqab — during the ceremony.

In both cases, the women had satisfied officials as to their identity prior to the official ceremony. This was good enough for the courts and it’s good enough for Justin Trudeau’s Liberals and Thomas Mulcair’s New Democrats

But it’s not good enough for many voters who, polls say, are overwhelmingly on the side of the Conservatives on this issue.

And it’s not just the Conservatives who are playing the niqab wedge to their political advantage. It is also Gilles Duceppe’s Bloc Quebecois. The BQ has some of the nastiest attack ads so far in this campaign attacking Mulcair and the NDP over the niqab.

And guess what? Several pollsters are pointing at this niqab issue to explain why the NDP has rapidly lost support in Quebec. A Leger poll published Friday found just 28% of Quebecers now support the NDP. The NDP had enjoyed support of nearly 50% of voters in that province mere weeks ago.

When the Orange Wave swept over Quebec in 2011 to make the NDP the official opposition, nearly 43% of Quebecers voted NDP.

Now, the NDP are facing grim prospects of being bounced to third-party status in the House of Commons.

Well, if Mulcair is going to go down, he showed Friday night — finally — that he’s going to go down fighting, delivering an impassioned defence of the right of those two women to stay veiled in public.

It was not only that moment but elsewhere in the two-hour debate, broadcast from Montreal by the country’s largest private-sector French language network TVA, that Mulcair’s tone, delivery, and style was largely spot-on. His party needed a performance like that after four earlier mediocre debate performances.

On the niqab, he prefaced his remarks by saying the issue of women staying veiled during a citizenship ceremony “makes me uncomfortable” and that many voters feel “queasy” about the idea.

That acknowledgement might help him a little in Quebec.

Still, winning points on style and passion while defending the values of the Charter of Rights and Freedoms may impress the pundit class but will it impress sceptical voters in French Canada?

“In an open society, one must from, time to time, show your identity,” Harper said, echoing what appears to be the majority view in Quebec. Indeed, as Harper noted, some of Mulcair’s own candidates in Quebec disagree with him on the niqab.

As for Trudeau, he, perhaps wisely, tried to keep his head down during the niqab segment of the debate. Though he agrees with Mulcair, he turned attacks from Duceppe on the niqab by saying there are more important economic issues in this campaign.

And Trudeau’s right. There are much more important issues. But for now, this is the wedge that may be separating a winner from a loser