A union is not some "outside organization". Union locals are led by people that come out of the workforce and are democratically elected. Bargaining committees

A union is not some "outside organization". Union locals are led by people that come out of the workforce and are democratically elected. Bargaining committees are elected by the workers, contracts are subject to ratification to workers, strikes can only be called with a strike authorization votes. Union nationals do have problems (e.g. UAW only just voted to move to a true one-person-one-vote system), but the nationals aren't really that important in the important areas. A union binds you to working together with your colleagues, not to some outside entity.