@Nzall depends on whether it's a minority or majority union. In a minority union you don't need to vote to unionize and the union only represents people who join it voluntarily. In a majority union the union represents the entire workforce, but there's a higher bar to create it in the first place.
Majority unions generally have significantly more power and, IIRC, historically most US trade unions have been majority unions.
No idea! Probably depends on where you are. I'd assume the answer is usually "yes" though.
It's probably more complicated than just instantiating as a majority union in the first place if you can, though
And as MBraedley points out there's a sort of minimum critical mass; a minority union with a population small enough that the employer can get away with firing all of them is just a target.
> The decision by the ethics panel could further complicate Mr. Gaetz’s attempts to fight the allegations and remain in his House seat. But the committee typically works slowly and poses far less legal or political risk than a Justice Department inquiry.