As the Liberals' re-election campaign was foundering last week, Andrew Scheer was promising that a Conservative government would spend $1.5 billion to reduce medical wait times.

It's a commitment that might stir some nostalgia. Stephen Harper's Conservatives identified reducing wait times as one of their top five priorities during the 2006 election. Once in government, the Conservatives committed $700 million in funding and signed agreements with the provinces.

Then everyone, including the Harper government, forgot about it.

Thirteen years later, with the Conservatives trying to get back into power, the issue of wait times is back on the agenda.

It's one of several familiar tunes on the party's playlist. Indeed, the early stages of Andrew Scheer's campaign have sounded, at times, like a medley of some of Stephen Harper's greatest hits.

There is a promise to restore, with minor tweaks, tax credits for users of public transit and for children's arts and fitness activities. There is a new tax credit for parents — this time to offset federal taxes on maternity benefits.

Scheer hasn't offered anything as catchy as Harper's GST cut yet, though he has committed to a "universal" cut to personal income taxes. And there is, as always, a full-throated condemnation of the Liberals' move to price carbon emissions.

This isn't entirely surprising. In general, political parties are seldom quick to reinvent themselves. In this case, Scheer's campaign for the Conservative leadership was premised on the idea that the party's defeat in 2015 had nothing to do with its policies.

But the Harper agenda — defined by a focus on targeted and marketable tax cuts and limited interest in using the resources of the federal government to do other things — was also rather successful at winning elections in 2006, 2008 and 2011.

The question now is whether it's still enough to win in 2019.

Keeping the base intact

A lot changed in federal politics between 2006 and 2015, but one thing remained relatively constant: the number of people voting for the Conservative Party of Canada.

In 2006, when Harper's Conservatives dislodged the previous Liberal government, Conservative candidates received a total of 5.4 million votes. Two years later, the Conservatives retained power with 5.2 million votes.

Three years after that, Harper won a majority with 5.8 million votes. The Conservatives then received 5.6 million votes in 2015, but lost power.

The other half of the story of those nine years — the difference between a Conservative majority in 2011 and defeat in 2015 — is told in the Liberal vote, which fell precipitously from 4.5 million to 3.6 million to 2.8 million and then surged dramatically to 6.8 million.

The Conservatives have invested heavily in driving that number down, or at least dispersing it, with an ad campaign that insists Justin Trudeau is "not as advertised." Scheer doesn't need disappointed Liberal voters to go to the Conservatives this time — he just needs them to stay home, or vote NDP or Green. Last week's blackface images likely will only help the Conservatives make the argument that Trudeau is not who he seemed to be.

"Choose forward" is the Liberal response, an implicit invitation to contrast Trudeau and Harper. It remains to be seen whether Trudeau has shown enough in the last four years — or whether Scheer seems threatening enough — for that to resonate with progressive-minded voters.

In the meantime, Scheer hasn't been acting like a leader who is eager to dramatically expand his party's appeal.

The current Conservative leader is not a mere facsimile of Stephen Harper. As promised, Scheer smiles more often than his former boss did. In the current campaign, he also has seemed more tolerant of the travelling media.

Prime Minister Stephen Harper waves after giving his victory speech following the Conservatives' majority win in Calgary on Monday, May 2, 2011. (Adrian Wyld/Canadian Press)

He has not suggested eliminating the long-form census and hasn't promised to reintroduce a ban on the niqab during the swearing of the citizenship oath (though he did decide to oppose the UN's global compact on migration, joining the company of various far-right European parties and governments who criticized a non-binding statement of principles).

But while trying to cast the Conservative Party in a slightly softer light, he has eschewed his biggest policy opportunity to make a significant break from the Harper era: climate change.

While the Conservatives are touting a 60-page climate policy document that features many words, the actual policies it contains would lead to a significantly smaller reduction in Canada's carbon emissions over the next decade — or even to an increase in emissions. Canada's international target for 2030 would be missed by a wide margin.

The Bernier factor

In that respect, Scheer has barely deviated from Harper's passive post-2008 approach to climate policy.

On Friday, during an event in Nova Scotia, Conservative supporters insisted on standing in front of a handful of people who had come to one of Scheer's events holding signs that raised concerns about our warming climate. While Scheer likes to insist that he has a real plan for combating climate change, that scene in Nova Scotia suggests Conservative supporters still see themselves standing in opposition to those who worry about global warming.

Conservatives who have been stewing in anti-carbon pricing rhetoric for a decade might be hard to move toward a more aggressive approach to climate change (and non-pricing approaches have the downside of actually being more expensive). Scheer and his advisers might simply have been unable to resist the opportunity to run against a "carbon tax."

But they also might have been worrying about Maxime Bernier, their rival on the right. Bernier doesn't just oppose implementing a price on carbon — he actively dismisses the science and the threat of climate change. Though the People's Party has shown little sign so far of breaking out, it's theoretically in a position to siphon off the votes of Conservatives who don't think Scheer is conservative enough. In such a close election, every percentage point matters.

Whatever the cause, the result is that 2019 shapes up as something of a rematch of 2015. The participants are slightly different, but the agendas and the ideas are broadly the same.

Put another way, it's a test of which is more durable: the Conservative Party that Stephen Harper built after 2006, or the Liberal Party that Trudeau brought to power four years ago.