Nearly 70 years later, experts say attacks of another sort have left those unions fighting for their very survival.
The continuing rise of multinational corporations, growing public apathy toward the labour movement and unprecedented interference from the federal government have forced leaders in the country's labour movement to consider new strategies in order to stay afloat during turbulent times.
Two of Canada's largest private sector unions formally acted on a long-simmering plan last week to merge the two organizations.
In outlining a plan to officially join forces by 2013, the Canadian Auto Workers Union and the Communications, Energy and Paperworkers Union of Canada said the merger was necessary to combat what they described as growing hostility from the country's corporate and political ranks.
If anything, veteran union watchers believe the CAW and CEP understated the gravity of the situation.
Former CAW president Buzz Hargrove said he has never witnessed such widespread anti-union sentiment in his many decades of involvement with organized labour.
That antipathy has been most clearly demonstrated by the Federal government, he said, citing pieces of legislation forced through Parliament that effectively ended labour disputes at Air Canada, Canadian Pacific Railway and Canada Post on employer-friendly terms.
Such aggressive political action, he said, is designed to create a climate similar to the one that has taken shape in the United States where unionized workers now make up less than seven per cent of the private sector workforce.
"I think the business community watched what's happened in the U.S. and said, 'We haven't been aggressive enough in Canada. We can do the same thing with the support of the governments,'" Hargrove said in a telephone interview.
"And they got the support of government, and they're moving ahead with that."
Hargrove said the past five years have seen an unprecedented spike in labour disputes centred around employers wanting to claw back salaries or benefits.
Some of the more bruising disputes have hobbled industry and left workers out of a job for months, he said.
A strike by employees of mining giant Vale brought local commerce to its knees in the northern city of Sudbury, Ont., for nearly a year between the summers of 2009 and 2010, while a lockout initiated by U.S. Steel kept workers at home for more than 12 months.
Unions claimed defeat in both cases, saying members were losing out on lucrative salary structures or future pension arrangements.
Hargrove said the federal government's well-documented anti-union stance has emboldened companies to take a hard line against unions.
Provincial governments have also followed their example, he said, citing Ontario Premier Dalton McGuinty's recent threat that he could recall the legislature in order to force an end to collective bargaining between the province and its teachers.
University of Toronto historian Laurel MacDowell, however, said the issue is more nuanced.
Companies swept up in the tide of globalization have been eager to shift their operations from North America to overseas locales with cheaper labour costs, she said, adding such moves put unions in significantly weaker bargaining positions and greatly complicate any efforts to organize.
The makeup of the economy has also shifted in favour of today's most prevalent employers, MacDowell said.
Unions formed after the end of the Second World War were built around the largely manufacturing-based economy that existed in those days. The landscape is now dominated by service-oriented companies, MacDowell said, noting many of them are notoriously opposed to letting their workers organize.
"They have this highly individualized notion of how relationships work and are simply not going to deal with unions," she said.
The deterioration of Canada's labour movement is noticeable, but still a far cry from conditions south of the border, she said.
Employees on Wal-Mart's Canadian payroll were the first in North America to land union certification. The retail giant, whose anti-union stance is well documented in the industry, shuttered the store in question shortly afterward and has largely stymied other locations' attempt to follow suit.
Union participation represents 30 per cent of the Canadian workforce, according to the CAW — well above levels in the U.S.
Still, the numbers have declined from an all-time high of 40 per cent registered in the late 1970s. MacDowell said existing trends point towards a continuing decline that will leave the current generation of labour activists fighting to hold territory first staked by their grandparents.
"If there isn't support from the government to back up the legislation, and there's real opposition from the corporate sector, the workers on their own can't really do it. And the unions are finding it very difficult to maintain essentially gains that they won in the 40s," she said.
Hargrove believes the CAW and CEP merger is a step in the right direction.
By combining resources and creating a union with more than 300,000 members, Hargrove said the two labour movement stalwarts will give the rest of their compatriots a much-needed shot in the arm while creating an organization that's able to stand toe-to-toe with governments and corporations.
"We have to concentrate our resources. We have to focus and make sure that wherever we can come together as a labour movement and take on a battle, that we do."
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