The Harper government's post-mortem began in earnest Tuesday morning as the reality of a defeat to Justin Trudeau's Liberals began to sink in for various Conservative candidates.

Trudeau will be Canada's next prime minister after leading the Liberal Party to a majority government after capturing 184 seats in Monday's election.

​Outgoing Prime Minister Stephen Harper will continue to sit as an MP as the party moves to select an interim leader.

"We put everything on the table, we gave everything we had to give, and we have no regrets whatsoever," Harper said of the 78-day campaign during his concession speech Monday night.

"The disappointment you also feel is my responsibility and mine only," he told supporters.

During an interview on CBC Radio's call-in noon program Ontario Today, re-elected Conservative candidate Lisa Raitt said the party will have to take the time to determine the reasons for the defeat.

WATCH: Highlights from Harper's concession speech3:02

"Look, we lost," Raitt told host Rita Celli, "and we have to figure out what happened in order for us to make sure that we can bring those great policies back that we have of being fiscally Conservative."

Some callers who identified themselves as Conservative supporters put the blame squarely on Harper's shoulders.

"[The caller] is saying a lot of different things," said host Rita Celli to Raitt, "but still she wanted your team to still be in power. Can you learn from something she's saying? She said Stephen Harper didn't fight hard enough."

"One hundred per cent," replied Raitt.

Raitt, who served as transport minister in Harper's cabinet, questioned whether her government did a good job of reaching out. "I don't know whether or not our party and our government did a good job of communicating with women like me," she said.

"We probably didn't get a lot of the vote of my people," said Raitt, "the women like me between the ages of 18 and 49 years old."

Not 'a referendum' on Conservative economic record

Conservative Erin O'Toole, who was re-elected Monday, said it was difficult to celebrate knowing many of his colleagues had been defeated.

O'Toole, who served as veterans affairs minister before the election was called, said the party will have to ask itself several questions.

"As a team, the Conservatives, we're going to have to learn from this," said O'Toole on Ontario Today.

"Why could we not run on a record that was pretty darn good on a lot of economic issues, trade issues, security issues, things like this. Why was there this push for change?" O'Toole told Celli.

'I don't think it was, frankly, a referendum on our economic performance'
- Joe Oliver, former finance minister and defeated Conservative candidate

Former finance minister Joe Oliver was defeated by Liberal Marco Mendicino, a lawyer who won the nomination over Eve Adams, a controversial former Conservative who crossed the floor to join the Liberals earlier this year.

Oliver, who was also on Ontario Today, said Monday's results were not a vote against the party's economic record.

"I don't think it was, frankly, a referendum on our economic performance."

"The fact that we had been in government for almost 10 years, resentments can start accumulating and people just wanted to see some new faces," said Oliver on Tuesday afternoon.

"I'm not certain that this was a resounding vote for higher taxes and massive deficits, but it is of course what the Liberal platform proposed and therefore we have to brace ourselves for that."

Oliver would not say whether it was a mistake for Harper to run again in this election.

"It's certainly true that it becomes increasingly difficult the longer a government is in power to retain its popularity. And that was a key factor in this election."

Conservative MP Laurie Hawn, who did not run again in this election, said Harper was both the party's greatest asset as well as its greatest liability.

Hawn conceded the Conservatives "went too far in a couple of areas" citing the the issue of women wearing the niqab at citizenship ceremonies, which he characterized as "a sideshow."

"I think all we did with that was we alienated some of our softer support," said Hawn.