The five candidates running to be the next leader of the federal New Democratic Party launched into their Toronto debate by attacking the way Prime Minister Justin Trudeau has dealt with U.S. President Donald Trump, while also raising the issues of taxation and trade.

While not one of the party's official events, Thursday evening's sparring contest is the only debate between the candidates being held in Toronto. It focused in on the themes of the economy and labour.

The five candidates participating in the debate, hosted by the United Steelworkers union, were:

Manitoba MP Niki Ashton.

Ontario MP Charlie Angus.

Quebec MP Guy Caron.

B.C. MP Peter Julian.

Ontario NDP MPP Jagmeet Singh.

During a direct exchange between candidates, Singh came under attack from Ashton, who said the current tax system was "rigged against working people." She accused Singh of not being aggressive enough in his plan to raise taxes.

Singh proposed to increase corporate taxes, introduce an estate tax for estates over $4 million and create two new tax brackets — one for people who earn over $350,000 and one for those earning more than $500,000. He said that was a starting point and that he was open to ideas.

"I agree with you on the point that we need tax fairness, but why aren't we going further?" Ashton asked. "Why not treat capital gains from flipping homes the same as working income, at 100 per cent?"

Singh proposes raising the amount of capital gains income that is taxable, currently 50 per cent, to 75 per cent.

Trudeau and Trump

The candidates were asked how they would criticize Prime Minister Justin Trudeau's approach to dealing with U.S. President Donald Trump.

Ashton, Singh and Angus said they would stand up to Trump and not simply "jump" when the U.S. president tells Canada it needs to spend more money on the military.

"Talk about spineless," Ashton said of Trudeau's approach to the U.S. president. "Trump is a bully and what do you do with a bully? You stand up to them."

Ashton went on to say that Trudeau was not standing up to Trump on NAFTA, before offering, "We don't know what [Trudeau] is doing on NAFTA."

Julian said Trudeau's approach was "appallingly weak," and that the prime minister was "not standing up for Canadian jobs, not standing up for Canadian communities"

Caron said he preferred former prime minister Pierre Trudeau's approach to dealing with the U.S., which was to stand by Cuba and not stand in line behind the U.S.

'Buy Canada'

Julian and Singh said they would back a "Buy Canada" policy in response to Trump's moves south of the border.

Singh said that policy should start with Canadian steel, but should be expanded to other areas, including softwood lumber.

Julian said a "Buy Canada" policy could work within any trade deal with the U.S. and would give Canada leverage in those deals.

On Indigenous issues, Julian said an NDP government would act quickly to deal with emergencies like the lack of clean water available in many First Nations communities and the lack of adequate mental health care.

Ashton said that if elected party leader, and then prime minister, she would move quickly to adopt and implement the United Nations Declaration on the Rights of Indigenous Peoples.

Pensions and precarious work

Singh was questioned by Caron over his policy proposal to merge all existing benefits for seniors into one single benefit that was not universal, but would be scaled to a person's income, providing more money to those who need it most.

Caron said ending the universality of Old Age Security was a "Conservative idea, and I would like to know why you are trying to dress up a Conservative idea in progressive clothing."

Singh responded that under the current system seniors were living in poverty, because the benefits system was giving money to those who did not need it rather than targeting those who need it most.

Angus said problems with contract work could be fixed by reworking the tax code, but was short on specifics.

Julian said the way to ensure Canadians have more secure incomes was to make it easier for them to join unions and to enact anti-scab legislation.

Ashton said free university tuition would help end precarious work by creating a better-trained workforce, while Caron said he could fix the expanding culture of contract work by creating more green jobs.

As for how the party would keep and expand its seats in Quebec, Singh flagged his ability to speak French and touted his respect for French-Canadian culture, but offered few specifics.

Ashton said that the social and labour movements in Quebec were strong and the NDP had to align itself with those movements more effectively.

Caron said the NDP was hurt in the last election because it did not have a specific platform aimed at Quebec, and it needed to change that approach before the next election.

4 debates remain

The debate was moderated by two steelworkers, Mark Rowlinson and Fatima Gulaid, who put questions to the candidates that had been previously crafted by members of the United Steelworkers.

There are four remaining official debates between the leaders coming up. They will be held in Saskatoon on July 11, Victoria on Aug. 2, Montreal on Aug. 27 and Vancouver on Sept. 10.

NDP members will pick a new leader in the fall through a preferential, ranked ballot system. Voting will take place online and by mail in rounds held over several weeks.