Prime Minister Stephen Harper's handpicked parliamentary secretary says the Conservative Party's focus on identity issues — the niqab, stripping citizenship from dual nationals and launching a barbaric cultural practices hot line — was a mistake that cost the party votes among new Canadians.

"There was a lot of confusion and a lot of first-generation Canadians said 'OK, we're not ready to endorse that,'" Paul Calandra said in an interview with Rosemary Barton on CBC News Network's Power & Politics.

"Obviously, yeah, in retrospect [it was a mistake]," he said, and one that likely led to his defeat at the hands of his Liberal opponent, Jane Philpott, in the riding of Markham–Stouffville.

"We had our challenges, obviously, in the early goings — we had the Duffy trial, then the Syrian refugee crisis — but through it all we were still in a very good spot," Calandra said.

Voters were responding to Conservative messaging around low taxes, the economy and public safety, he said, but then the party started to stray into identity politics, and doubled down on rhetoric about Islamic face coverings and homegrown terrorism.

The Strengthening Canadian Citizenship Act was a particular sticking point. The Conservative-drafted law, known during the legislative process as Bill C-24, strips dual nationals of their citizenship if they are convicted of terrorism or high treason, among other serious offences.

It was not that voters disagreed with what the Conservatives had enacted, but that they were "confused" about how widely the law could be applied, Calandra said, and the Liberals pounced, shrewdly denouncing the policy as a slippery slope that created two classes of citizenship.

"'What does it mean for me? How will that impact my family,'" Calandra said, reciting some of the questions he heard from voters at the door. "I had a call ... 'If I'm caught shoplifting does that mean my family has to go?'"

Calandra said he and his campaign staff did not have the time, during the cut and thrust of the election campaign, to explain each of these controversial policies to concerned voters.

"You know, individually, taken in isolation ... if you could spend five minutes at the door explaining Bill C-24, explaining why you needed to remove the niqab at a citizenship ceremony, explaining what we meant by 'barbaric,' if you could do that, then you could turn a voter.

"But in the context of, you know, 10 days left in an election — it was just people saying 'Look, we're not ready to endorse that yet, we want to go back to a pre-C-24 status quo,'" Calandra said.

"And you could see it towards the end, you would come back from a canvass and there would be a lot more undecided [voters]."

'Grateful' for role as PM's spokesman

Calandra, first elected in the 2008 federal election, became parliamentary secretary to the prime minister in 2013 after his predecessor, Pierre Poilievre, was elevated to the cabinet.

Stephen Harper's outgoing parliamentary secretary, Paul Calandra, says he has no regrets about his role during the Wright-Duffy affair. 3:55

The role includes fielding tough questions from the opposition, and the media, on some of the more sensitive files.

He said he thought at the outset of the campaign the controversial role might have been a "lightning rod" or a source of anger from voters in his riding but those fears were unfounded.

During his tenure, the Wright-Duffy affair dominated the headlines, and Calandra often faced the prosecutorial NDP Leader Tom Mulcair.

"When you talk about the Senate issue, we just didn't have answers, sometimes," he told Barton.

"And one thing the prime minister told me right from the beginning, when I took the job, was never lie to people. 'If you don't know the answer, then don't answer it. If you don't know, don't make anything up.'"

Calandra said he never really tired of repeating talking points, or serving as a punching bag, rather he was grateful to serve at the behest of the prime minister.

"That's just my personality, I loved every minute of being in the House of Commons, being in the thick of things," Calandra said.

"And knowing that my caucus colleagues were going through a pretty miserable time in question period, if there was some way to alleviate that ... with a little humour, or levity, then I would do that. I loved it."

Calandra said the one exception was an incident that sparked widespread criticism after he replied to a question from Mulcair on Canada's mission in Iraq with a bizarre answer about Israel, alleging an NDP fundraiser accused the Jewish state of "genocide."

He later made a tearful apology in the House.

Paul Calandra, Stephen Harper's parliamentary secretary, makes an emotional apology in the House for his question period responses to NDP Leader Tom Mulcair this week. 1:35

But despite the rough go, Calandra said that this would not be his last campaign and looked forward to returning to electoral politics.