when america was going thru the industrial revolution employers treated workers like slaves. unions saved the day. today the workplace is so open that workers freedom to move from job to job enforces a competition among employees to offer better wages, conditions and benefits.
therefor, unions are just leaches that skim money from both employers and workers without giving anything you would'nt get anyway. in america there is no need for unions any more.
look at delta airlines...long term pilots have built up their salaries only to reach a point where they are making so much money that it bugs the financial crap out of delta. union rules prohibit delta from replacing a 58 year old pilot making 110k with a 32 year old making 48k. so delta plans bankruptcy which will allow them to force 58 year old pilot to work for 65k. the union is powerless and is the first one to agree in order to keep the union dues flowing. so now, instead of just delta fighting to stay alive and the pilot fighting to stay alive...you have the union fighting to stay alive - at who's expense?