Conservative Leader Andrew Scheer ran his party's federal election campaign as a referendum on the performance of Justin Trudeau and the Liberals over the last four years.

Now the results are in: a minority government for Trudeau, a slightly larger caucus for the Conservatives — and new pressure on Scheer's leadership.

Beyond a promise to voters to make life more affordable through tax cuts, Scheer said Canadians should back Conservatives in this election because Trudeau had lost the "moral authority to govern" after the SNC-Lavalin scandal and the brownface photos surfaced. A substantial number of Canadians disagreed.

While Scheer did not pick up enough seats to form a government, he did hold Trudeau to a minority. But more than that, the Conservative Party appears to have won the popular vote thanks in part to lopsided victories in the West.

In his address to party supporters Monday, Scheer gave no indication that he would be resigning his position as leader.

"While tonight's result isn't what we wanted, I'm also incredibly proud, proud of our team and proud of the bigger and stronger Conservative team that we'll send to Ottawa," Scheer said.

Andrew Scheer says the Conservatives are the 'government in waiting'

Conservative Leader Andrew Scheer says he's looking forward to heading back to Ottawa with a bigger Conservative team while speaking to reporters in Regina, Sask. 1:29

"Tonight, Conservatives have put Justin Trudeau on notice and Mr. Trudeau, when your government falls, Conservatives will be ready and we will win."

Scheer failed to substantially bolster his party's standings in the House of Commons. The Conservatives return to Parliament with roughly 20 more seats than former prime minister Stephen Harper won in 2015.

In once deep-blue ridings in places like Atlantic Canada and Ontario, Liberal candidates managed to fight off their Conservative challengers. The party failed to make any gains in Quebec. Deputy party leader Lisa Raitt, a Conservative stalwart and a Red Tory, went down to defeat in the suburban Toronto riding of Milton.

Conservative Deputy Leader Lisa Raitt loses in Milton, Ont.

In her concession speech, Ontario Conservative candidate Lisa Raitt says it has been an honour to serve as the deputy leader of her party. 0:51

The Conservative election strategy — sticking to tried-and-true Conservative policies like tax cuts while rejecting substantive climate action to motivate the dedicated Tory base — failed to sway enough independent-minded voters in Central and Eastern Canada.

Scheer was able to tap into the palpable anger in Western Canada — particularly in the Prairies, where the Liberal government has been accused of stifling the oil and gas sector with policies like the northern B.C. oil tanker ban and the controversial overhaul of the environmental assessment regime.

Conservative candidates toppled all Liberal MPs in Alberta and Saskatchewan, including long-time Liberal MP and cabinet minister Ralph Goodale. In Alberta, Conservative candidates secured an eye-popping 70 per cent of the vote. In Saskatchewan, Tories swept all the seats with more than 67 per cent of the vote.

But Scheer's future as Conservative leader is now in doubt.

Scheer said Monday's result is just the "first step" and the popular vote success of the party in this election means that the Conservatives are now the "government in waiting."

Under the Conservative Party constitution, if the party fails to form government — and if the leader has not yet formally signalled an intention to resign — then delegates can vote at the next party convention to hold a leadership race. If more more than 50 per cent of the votes cast at the convention favour such an option, that would trigger a leadership race.

Of course, Scheer might resign before that leadership review vote is even necessary.

Andrew Scheer's full election night speech

Conservative Leader Andrew Scheer speaks to supporters in Regina, Sask. Scheer won his Regina-Qu'Appelle riding. 10:44

While Trudeau's campaign was beset by scandal, Scheer also faced questions about his resume and his political positions. Scheer appeared awkward when asked about social issues like gay marriage and abortion. There were also questions about his past as an insurance broker (he was never actually licensed to sell insurance) and his dual Canada-U.S. citizenship.

Scheer was first elected in his adopted hometown of Regina in 2004, beating long-time NDP MP Lorne Nystrom.

After years on the Conservative backbench in opposition and then in government, Scheer served as deputy speaker in the House of Commons before taking the big chair himself after the 2011 election.

Conservative party members were forced to pick a new leader after their electoral thumping in 2015. At the outset of that leadership race, Scheer struggled to stand out in the crowded field of 17 candidates who were vying to replace Stephen Harper.

Scheer, while Speaker of the House of Commons, jokingly tries to fight with then-prime minister Stephen Harper and then-NDP leader Jack Layton as they escort him to the Speaker's chair in June 2011. (Adrian Wyld/Canadian Press)

With media attention focused on higher-profile candidates like Kellie Leitch, Kevin O'Leary and Maxime Bernier, Scheer quietly assembled a significant amount of "second choice" support among members.

He courted socially conservative voters — a not-insignificant portion of the Conservative leadership voting base — but also more moderate elements of the party who feared Bernier's strident libertarianism would be a turn-off for the general voting public. He narrowly beat Bernier by less than two points on the 13th and final ballot.

Scheer acknowledged early on that his policy proposals were not all that different from those of his predecessor. He willingly embraced the "Stephen Harper with a smile" label, saying he would govern like Harper but with a less stern image.

When he assumed the helm of his party, the Liberals were still flying high in the polls.

Scheer is congratulated by Maxime Bernier after being elected the new leader of the federal Conservative party in 2017. (Frank Gunn/Canadian Press)

But Scheer scored some wins as an opposition leader, like a come-from-behind victory in a Quebec byelection. He capitalized on Liberal scandals — like Trudeau's much-maligned trip to India — and some ethical lapses, like Trudeau's trip to a private island in the Bahamas.

With the SNC-Lavalin affair, Scheer sought to paint Trudeau as a man unfit to govern after inappropriately pressuring his justice minister. His efforts paid off in the early months of 2019 as Liberal popular support numbers dipped significantly.

Scheer launched the election campaign with a promise to make life more affordable for Canadians ("It's time for you to get ahead" was the chosen slogan), by promising to revive Harper-era policies that were dismantled by the Liberals.

Scheer committed to a children's fitness and arts tax credit, a public transit tax credit, a new green home retrofit tax credit and a "universal tax cut" to slash income taxes for middle-income Canadians.