The labour movement has been put on the defensive as globalization and economic downturns have steadily eroded their bargaining power, and the advent of a Conservative government with a strong antipathy to unions.
Federal data shows the unionization rate has declined slowly but steadily in the last 15 years, with just under one in three Canadian workers belonging to a union or covered by a collective agreement. The gap is largest in the private sector, with just 16 per cent of employees unionized, compared with 71 per cent in the public sector, CBC News reported in 2012.
So labour is likely to cheer Friday's Supreme Court of Canada ruling that upheld the right of unions to single out members who cross a picket line during a strike or lockout.
The high court struck down Alberta's Personal Information Protection Act, ruling that a union has the right to photograph or videotape people who cross the line.
The decision is an important victory for unions, who have fewer and fewer tools to keep members in line during a labour dispute.
Courts routinely grant orders that limit the number and location of pickets. And the Supreme Court refused to hear an appeal of an Ontario ruling that struck down a union's ability to levy fines against members who cross picket lines.
But this time, the Supreme Court sided unanimously with an Edmonton local of the United Food and Commercial Workers, which was trying to discourage members from going to work during a 2006 strike at the Palace Casino that lasted 305 days.
According to The Canadian Press, the union had posted signs warning strike-breaking members their faces might be posted on a union web site. They never were, the Edmonton Journal said, but some images were used on posters during the strike, and newsletters and leaflets.
Several members complained to the Alberta's information and privacy commissioner, citing the province's then fairly new Personal Information Protection Act.
The legislation was intended primarily to safeguard the collection of private information from citizens by businesses and institutions.
An adjudicator appointed by the privacy commissioner sided with the line-crossers, ruling the union had violated the law, CP said. But Alberta's courts threw out the decision, granting the union a constitutional exemption.
In a 9-0 decision, the Supreme Court ruled the entire act was problematic and gave the Alberta government a year to change it.
The law imposed unacceptable restrictions on the union's ability to communicate and promote its case in a legal strike, the court said, according to CP. While the act is intended to give people some control over their personal information "the price [it] exacts, however, is disproportionate to the benefits it promotes."
“This infringement of the right of freedom of expression is disproportionate to the government’s objective of providing individuals with control over the personal information that they expose by crossing a picket line,” says the ruling.
Union lawyer Gwen Gray praised the ruling.
"It is a very important decision for not just trade unions, but any kind of public organization or people's organization," she told CP.
She told the Journal she was surprised the decision was unanimous, which is quite unusual.
“Freedom of expression is really the only tool unions have to make a difference," she said. "The only tool they have in their buckets is speech.”
The decision may be the biggest labour victory since the Supreme Court in 2007 threw out sections of a 2002 B.C. law that unilaterally tore up the provincial government's contract with the Hospital Employees Union, opening the door to thousands of layoffs.
The court ruled the Charter of Rights and Freedoms protects the collective-bargaining process and the law, known as Bill 29, undermined the process, CBC News reported at the time.
Friday's decision might be seen by some as making union members vulnerable to intimidation if they oppose a strike.
Certainly the strike is the only real weapon unions have if collective bargaining breaks down.
Pickets usually aren't allowed to physically prevent people from crossing the line but the effectiveness of a strike depends on solidarity. Members who derive benefits from the contract-negotiation process should, theoretically at least, feel some obligation to stand with their union once the majority has voted to strike.
That can sometimes involve sacrifice, but the alternative is to render the union toothless. Those who want the gains won through bargaining and, if necessary, strikes, but then play both sides should be prepared to face some push-back.