But I'm not sure the union is going to be on my side. I know that's their pitch, but lots of people claim they want to act on my behalf - I'd be a fool to trust most of them!
This just isn't true.
If I'm a junior worker in a union with a pay-by-seniority agreement because the majority of workers are senior, then they aren't on my side are they? They're on the side of the majority senior workers. They're on the side against me and my aspirations to get paid more.
If you aren't, check the agreements the union has with you and your employer. These are contracts with enforceable terms and are upheld.
Stop and think this through for just a second.
Try this thought experiment:
If I want dogs in the office and my colleague wants dogs banned, you’re telling me you think the union will simultaneously negotiate for both our positions with our employer?
Does not compute. It is not possible for them to be on everyone's side.
Consensus-building and making of viable compromises has always been part of governance, any institution comprises people with diverse, sometimes competing interests.
That said, the usual workplace conflict between employee and management is about working conditions and promotion. And for that it's useful to have a paid witness on your side, because HR is always working for the employer.
Codes of conduct are fashionable these days, but at the end of the day they are upheld by HR, which will always work in favour of the company.