Contrary to what you might read in your morning paper, unions don't have much influence.
Look at this story about the former Nanticoke Stelco Works for example. Now a part of US Steel, the company is embarking on a plan to starve the Steelworkers union that represents the Nanticoke workers into submission.
There's nothing illegal about what they're doing. USS has steel plants all over the world. They can well afford to starve their Canadian workers while supplying their customers from other plants in their worldwide network.
That's the beauty of globalization. Your workers in one country get too uppity, you simply freeze them out till they come to their senses.
Full disclosure; in past lives I was a paid up member of the United Steelworkers of America in various locals: Dayton Steel, Dresser, Sandvik, Frankel Steel, Kearney National, to name just a few.
Thirty years ago the USWA was a heavyweight union that was taken seriously by the folks on the other side of the table.
Today it's just another spent force in the ranks of organized labour, happy to negotiate contracts for minimum wage plus a buck or two on behalf of what's left of their membership.