The leaders of Canada’s four national parties squared off in Toronto Thursday evening at a debate that focused mostly on the economy, environment, Senate scandal and terrorism.

In the first segment of the debate, Liberal Leader Justin Trudeau said the key question for Canadians is whether “Stephen Harper’s plan (is) working for you.”

Trudeau said that “wages are shrinking” and Canada needs a “fresh approach.”

The Liberal leader said his party is the only one committed to lowering taxes on the middle class by taxing wealthier citizens.

“The only risk right now would be to stick to what has been a failed plan for 10 years,” Trudeau said.

NDP Leader Tom Mulcair also said “Mr. Harper’s plan isn’t working.”

Mulcair said Canada lost 400,000 “well-paid manufacturing jobs” under Harper’s watch.

The NDP leader said Harper’s job creation record is “the worst since the Second World War.”

Mulcair promised the NDP would invest in infrastructure, cut taxes for small businesses and champion manufacturing technologies including green energy.

Green Party Leader Elizabeth May said Canada is in a recession, and that it’s time to “build up Canada’s economy through investment.”

“We need investment from the public sector. We need to invest in a climate action plan. Frankly, we need an army of carpenters, electricians and contractors going out to plug leaky buildings,” she said.

May said she was “not very” concerned about running a deficit.

“We have a weak and shrinking economy and it’s the wrong time for austerity measures,” she said.

Harper defended his record, while admitting that “we have weakness obviously in the energy sector because of the fall in the energy prices.”

“The way you deal with this is by sticking with a plan that is working, a low-tax prudent plan that is working,” he said, “rather than go to a plan of high tax and high deficits that’s failing everywhere else.”

Harper attributed Canada’s “1.3 million net new jobs” since the recession in part to tax cuts, and warned that “the other guys” want to impose taxes that would “kill jobs and hurt ordinary people.”

Pipelines and the environment

The second segment of the debate focused on where the leaders stand on a number of oil and gas pipeline projects that have faced opposition over environmental concerns.

Harper was asked whether the Keystone XL pipeline, which would carry Alberta crude oil to Texas, would have been approved by U.S. President Barack Obama had Canada imposed a nationally set price on carbon.

“Absolutely not. The president has never said that to me,” Harper said, adding that he believes Obama will “simply make a decision that’s in America’s best interest.”

Harper said he is “optimistic in the long run about the future of that project,” adding that he believes “whoever is the next president will approve that project very soon in their mandate.”

Harper warned that his opponents would impose carbon taxes that will increase the cost of “gasoline, home heating, groceries -- you name it.”

The Conservative leader accused his rivals of opposing pipeline projects “before we’ve even had environmental assessments.”

May attacked both Harper and Mulcair’s positions on pipelines, taking aim squarely at Mulcair on whether he supported the Kinder Morgan project proposed for B.C.

“It’s pretty straight forward,” May said. “They plan to put three times as many tankers moving out of Vancouver loaded with diluted bitumen, hazardous risky material.”

Mulcair responded that he had opposed a similar project when he was Quebec’s environment minister.

“With regard to these other projects, we have to be able to look at them objectively through a credible environmental process,” he went on.

May fired back: “So you take no position?”

“I am taking the position that you can study these projects,” the NDP leader said.

“Ms. May takes the position that you can say no to all of them in advance,” Mulcair added. “Mr. Harper is taking the position you can say yes to them all in advance.”

Trudeau took aim at both Mulcair and Harper, saying the Conservative leader “hasn’t been able to get it done on the environment” and accusing the NDP leader of “inconsistency.”

Trudeau pointed to the Energy East project, which would ship crude oil from Alberta and Saskatchewan to refineries in eastern Canada. The proposal is unpopular in Quebec.

“In English he’ll say he supports the Energy East pipeline,” Trudeau said of Mulcair. “In French he said that it’s out of the question.”

Mulcair responded that Energy East “could be a win-win-win,” offering better prices for producers, more royalties for the provinces, jobs and energy security.

Senate scandal

Harper was asked by the moderator whether he would apologize for appointing scandal-plagued senators. His answer was no.

“The Senate has been an institution that has had these kinds of problems for 150 years,” Harper said.

“When bad actions arise, the role of a leader is to take responsibility and hold people accountable and that’s exactly what we’re doing,” he added.

The top Conservative reiterated his position that he will not appoint any new senators, with the goal of putting pressure on the provinces to reform or abolish the institution.

May said that Harper’s decision to stop appointing senators is “unconstitutional.” However, she said dealing with the Senate is “not my top priority.”

Trudeau said the Senate can be reformed without “diving into constitutional reform” and that any future appointments should be done in a “transparent, non-partisan way.”

Mulcair said he supports abolition “pure and simple.”

“Mr. Trudeau thinks we need better senators,” the NDP leader said. “I think we need only former senators.”

Response to terrorism

Trudeau said Canada should have a role in fighting the Islamic State, but he does not agree with Harper’s approach.

“Unfortunately, Mr. Harper, as we’ve all seen, hasn’t seen a war he hasn’t wanted to get involved in,” the Liberal leader said.

Harper defended Canada’s contribution to the war in Iraq and Syria by saying NATO countries support the mission, and that ISIS has singled Canada out by name.

“It would be absolutely foolish for us not to go after this group,” Harper said.

Mulcair, meanwhile, said the current mission against ISIS is “not a NATO mission” and is a “wrong-headed approach.”

“Ms. May is opposed to every single possible use of our military, Mr. Harper is in favour of every single possible use of our military,” he said. “We will take a balanced approach.”

May focused on her opposition to Bill C-51, the Anti-terrorism Act passed in June that expands the powers of Canada’s spy agencies.

The Green leader said the legislation erodes the freedom of Canadians, adding “this legislation must be repealed.”

Mulcair, whose party voted against the legislation, agreed.

Trudeau admitted that voting in favour of Bill C-51 was “perhaps naive” and said he would repeal certain aspects of the bill.

“I think this is an issue that people are quite rightly worked up about,” he added.