To rephrase the popular Meghan Trainor song, when it comes to the Conservative campaign, the theory goes, it's always all about that base.

This is why EKOS pollster Frank Graves said that Harper's use of the term "old-stock Canadians" in Thursday's debate was a deliberate ploy to energize his supporters, part of the overall strategy to create a sense of us-versus-them.

Graves said it was the familiar "dog-whistle approach" — send out a message that will be ignored by all except its target audience.

But if that was Harper's intention, a kind of secret wink-wink to those in the Tory fold, then at least judging by the reaction, he blew a dog whistle of the wrong frequency. 

During the debate, on the issue of immigration, Harper denied his government had taken away those health-care benefits from immigrants and legitimate refugees, saying that those who had been refused were bogus refugee claimants.

"We do not offer them a better health-care plan than the ordinary Canadian can receive," Harper said. "I think that's something that both new and existing and old-stock Canadians can agree with."

​Harper explains 'old-stock Canadians' comment.1:32

The "old-stock Canadians" remark, instead of going unnoticed, immediately unleashed an onslaught of questions over what "old stock" meant, whether it had racist overtones and whether it was part of an overall Conservative campaign to engage in identity politics or stoke fears against other groups.

'He wants to talk about the economy. He doesn't want to talk about whether or not he's a racist.' - Communications consultant Gerry Nicholls on Stephen Harper

Identity politics, or the politics of division, have been blamed for the Harper government's fight against allowing Zunera Ishaq, a Muslim woman, to wear a niqab while swearing the oath of citizenship. On Friday, the Conservatives refused to budge on the issue, saying the government would seek a stay of a Federal Court of Appeal decision that would have allowed Ishaq to wear the niqab while swearing the oath of citizenship.

'Random things happen'

Meanwhile, Harper has been accused of playing to fears of others and using security concerns as an excuse to keep Canada's doors shut to the plight of thousands of Syrian refugees.

"The fact that he is once again choosing to divide Canadians and to use fear in his politics simply isn't worthy of a prime minister of Canada," Liberal Leader Justin Trudeau on Friday.

NDP Leader Tom Mulcair also called Harper's comments "very divisive language." 

"I think we're all Canadians and I don't like dividing people into categories like that," he said.

Harper accused of dividing Canadians2:03

Communications consultant Gerry Nicholls, who worked with Harper at the National Citizens Coalition, a conservative think-tank, suggested cheekily it's possible Harper's use of the "old stock" term was part of a secret plan, or that it was racist.

Or maybe, just maybe, he screwed up.

"People in politics think ... there's nothing done by chance, there's nothing random. It must be part of some of plan. Well, not always. Random things happen," Nicholls said.

"​I don't think there was anything sinister to it beyond the fact that it was just something Harper said. Considering all the stuff that's going on, he's probably wishing he hadn't said it because, if nothing else, it's getting him off-message. He wants to talk about the economy. He doesn't want to talk about whether or not he's a racist."

On Friday, Harper was clarifying his debate remarks, saying his old-stock comment referred to "Canadians who have been the descendants of immigrants for one or more generations."

However, Nicholls said he does believe the Conservatives are mildly playing the "us vs. them" card with some of these issues.

But he thinks there's a disconnect with the media and how a significant number of Canadians feel about the niqab ban, or the Syrian refugee crisis.

For example, a recent EKOS poll suggested the country was relatively split on whether Canada was taking in too many or just about the right number of Syrian refugees. And polls taken during the niqab controversy revealed a large number of Canadians sided with the Tories.

"I think it plays well, not only with his base, but it cuts well, it resonates well, appeals to people who might be voting Liberal or NDP. Those kind of issues work well for Harper."

And as for the Conservative base, Nicholls said one issue is probably riling it up the most.

"If anything is energizing his base, it's the media, Liberal and NDP attacks on Harper."

With files from The Canadian Press