In many union scenarios, the company would not be able to let go of workers even for productivity problems - nor would they be able to promote on the basis of a

In many union scenarios, the company would not be able to let go of workers even for productivity problems - nor would they be able to promote on the basis of ability or skill. The union decides who gets promoted, demoted - which is usually on the basis of 'time in' - and sets the rates for which jobs (and I mean exactly which jobs, i.e. you don't pick up a tool or do a task unless it's on paper that this task is 'your job'). FYI I'm speaking from the experience of a family member who was a Union Member at a Boeing plant - so this would be a fairly traditional late-20th century style North American Union, similar to auto-sector style unions.