Mulcair chose to address the Economic Club of Canada for his first major speech since being crowned NDP leader.
And he used the occasion to try to dispel the impression that the NDP is dogmatic in its opposition to resource development, trade and wealth generation — as the ruling Conservatives have repeatedly asserted in casting the social democrats as "unfit to govern."
"The NDP is resolutely in favour of development, as long as it's sustainable development," Mulcair told an audience of 200 that was heavily stocked with New Democrats.
"The NDP is resolutely in favour of trade, as long as it's fair trade. And the NDP is going to do everything it can to create a Canada that is more prosperous, as long as it's more prosperous for everyone."
That means, he explained, ending tax breaks for wealthy corporations, including enforceable provisions on labour rights and environmental protection in trade agreements, and requiring resource developments, such as Alberta's oil sands, to pick up the tab for environmental clean up.
"With that, I believe that together we can build a fairer Canada and a better world."
Mulcair said Canadians are comfortable with the NDP when it comes to social programs, some of which — notably universal health care — originated with the party. But he conceded they're less comfortable with the idea of putting the party in charge of running the economy of a major industrialized country.
"Some of the hesitation with regard to the party that often had the best ideas was whether or not we could manage a G7 country, whether we were capable of good, competent, public administration."
Speaking to reporters later, Mulcair said his message is part of his plan to reach out to Canadians who've balked at supporting the NDP in the past.
"Many Canadians share our goals, share our ideas and we want to make sure that we're able to reach out beyond our traditional base, ensure that people understand that, much as we've done in every province where we've been in power, we're capable of providing good, competent, public administration."
In a poke at the current interim Liberal leader, who once presided as NDP premier of Ontario, Mulcair added: "There might have been one exception, the Bob Rae government in Ontario.
"But overall, if you look at the NDP administrations across Canada, you'll see nothing but good, competent, public administration and balanced budgets and that's exactly the type of administration we're promising as of 2015."
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