The NDP leader promised that a New Democrat government would scrap the employee stock options deduction, a benefit enjoyed primarily by corporate executives that's worth more than $700 million each year.
That money would be redirected to low-income families by enhancing the working income tax benefit and the national child benefit supplement.
"This will be a dollar-for-dollar transfer in benefits from those who need it the least to those who need it the most," Mulcair told some 800 participants at the annual progress summit organized by the Broadbent Institute, a social democratic think-tank.
Mulcair cast the proposal as a "substantial measure" to reduce the gap between rich and poor Canadians and "a major step forward to take millions of Canadians, particularly children, out of poverty and into the middle class."
"The tremendous wealth that is being generated in this country today is landing into fewer and fewer hands," he said, calling the income gap "fundamentally un-Canadian."
"And those at the very top end are enjoying tax benefits that the majority just don't have access to."
More than 25 years ago, Mulcair noted that Parliament unanimously endorsed a motion by then NDP leader Ed Broadbent to eradicate child poverty by the year 2000. Yet, under Liberal and Conservative governments, he said the problem has only worsened.
Unlike the other main parties, Mulcair said an NDP government would actually take action to get the job done.
He took the opportunity to call on all progressive Canadians to unite behind the NDP, which has been stubbornly stalled in third place behind the Liberals and Conservatives in opinion polls over the past two years.
"We have never been as close as we are today to building the Canada of our dreams," Mulcair said, noting that a federal election is scheduled for October.
"But I need your help. I'm calling on each and every progressive Canadian to join me in this great endeavour."
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