Liberal Leader Justin Trudeau says he would invest in the middle class and grow the economy "from the heart outwards."

Conservative Leader Stephen Harper says stay the course and he'll put more money in your pockets.

NDP Leader Tom Mulcair says he has the best plan to trigger economic expansion.

With falling oil prices, a low dollar and uncertainty caused by more foreign currency market problems, all three leaders may be relying on some wishful thinking to fulfil their platform promises.

Speaking in Regina Wednesday morning, Trudeau said the Liberals want to remedy the economic challenges Canada now faces.

"We're proposing a strong and real plan, one that invests in the middle class, so we can grow the economy, not from the top down, the way Mr. Harper wants to, but from the heart outwards. That's what Canada has always done well," Trudeau said.

All three leaders may be relying on some wishful thinking to fulfil their platform promises, given the state of the Canadian economy and its likely effect on government finances.

The parliamentary budget officer has already revised this year's budget projections and expects a $1-billion deficit. That's likely to eat up the already reduced contingency fund, which the Conservatives lowered from $3 billion to $1 billion for 2015-16.

Recession, deficit likely

On Wednesday, the Canadian dollar is trading at around 77 cents US — it rose to 77.09 cents at midday after closing at 76.25 on Tuesday — and oil was trading around $43 US a barrel.

China's devaluation of its currency threatens to cause even more problems.

The Conservatives have been cautious, hinging many of their pledges on an improved government budget. Harper noted last week that he expects those pledges wouldn't be realized until "mid-mandate," or about two years after the election.

The Conservative leader also admitted last week that Canada is likely in a recession after being pressed in the leaders' debate by NDP Leader Tom Mulcair, who noted there has been five straight months of a shrinking economy. Six months or two straight quarters of contraction is the official definition of a recession.

Until that moment, Harper had avoided saying recession, pointing to projections that Canada will see overall growth for the year (the last two quarters are expected to be better than the first two).

Federal NDP Leader Tom Mulcair, right, speaks as NDP candidate Jean-Luc Daigle, left, looks on, in Lévis, Que. (Cameron MacIntosh/CBC News)

Trudeau too has hedged his bets, telling journalists last week that he is committed to balanced budgets, but can't guarantee them right off the bat.

"The Liberal Party recognizes that Stephen Harper has put us in deficit right now. We are committed to [a] balanced budget," he said on Friday.

"But how long it takes to get there will depend on the size of the mess Mr. Harper has left behind."

The Liberal leader said he's focused on tax cuts for the middle class and better child benefits for people who need them.

"[It's] why we're focused on putting money in the pockets of the families who will spend, save, grow the economy in meaningful ways, because that's how we will get out of this recession that Mr. Harper has created for us."

'Touch-feely slogan'

Mulcair, speaking in Quebec City, called Trudeau's approach "a unique perspective."

<a href="https://twitter.com/hashtag/Mulcair?src=hash">#Mulcair</a> responding to <a href="https://twitter.com/hashtag/trudeau?src=hash">#trudeau</a> economy from the heart comment <a href="https://twitter.com/hashtag/elxn42?src=hash">#elxn42</a> <a href="https://twitter.com/hashtag/cdnpoli?src=hash">#cdnpoli</a> <a href="https://twitter.com/hashtag/ndp?src=hash">#ndp</a> <a href="https://twitter.com/hashtag/lpc?src=hash">#lpc</a> <a href="http://t.co/V4F4MWYMro">pic.twitter.com/V4F4MWYMro</a> —@CamMacIntoshCBC

"The NDP has a real credible, solid plan to create jobs," he said. "We're not going to get those [lost] jobs back with a touchy-feely slogan."

At a rally in Edmonton later Wednesday, Harper also poked fun at Trudeau's "heart outwards" phrase, asking the Conservative crowd, "What is that?"

Gerry Butts, the principal adviser to Trudeau, tweeted his reply to Harper Wednesday evening, "Saying the middle class the heart of the Canadian economy is controversial? This explains a lot about the Harper Decade."

Neither Trudeau nor Mulcair offered much detail on how they would pay for their election promises given the lower-than-projected growth Canada has seen so far this year.

Mulcair said he can still cut business taxes and offer new social programs like universal daycare in a struggling economy, and said he'd release a costed platform later in the campaign.

He would not go into detail on how he'll pay for his promises, or whether those promises may need to be readjusted.

Precarious, low-paid jobs

"We've got a plan to kickstart the economy, to help small and medium-sized businesses create jobs, because they are the job creators," Mulcair said Wednesday at a campaign stop in Lévis, Que.

Those businesses create 80 per cent of new jobs in Canada, the NDP leader said, so the party wants to cut their federal tax rate from 11 per cent to nine per cent.

Conservatives are campaigning on the economy, arguing they are the only ones that can manage in tough times. Economic management is seen as one of the party's strengths, but with the faltering economy, the NDP and Liberals are just as happy as the Conservatives to talk about it.

"Mr. Harper's decisions have led to the loss of 400,000 well-paid manufacturing jobs in Canada.... The jobs that are being created are mostly part-time, precarious, low-paid jobs. They're not the types of jobs that allow a family to live and get by, and most of them come without a pension," Mulcair said.

And while none of the leaders want to be seen to support running a deficit, former parliamentary budget officer Kevin Page told CBC News a small deficit isn't something to worry about during a recession. At the same time, he said, no one should consider raising taxes to pay for campaign promises.

"We need a bit more realism. Maybe it's hard in the political environment to be realistic, but we need to be realistic," he said.

"Should we get growth above two per cent next year, and above two per cent the year after, then you go after some of this debt we've accumulated. But don't deal with it now. We are in recession," Page said.