It was? Then why can't bad cops or bad teachers be fired? Because I would consider that a critical feature of a union for public employees where the public interest is well-represented.

Just because they're a disaster now (which i am happy to admit -- police unions are a HUGE part of the problem we have with all police, everywhere. They're working against the best interests of the public -- and of cops too, ultimately) doesn't mean they can't be reimagined and rebuilt from the ground up, using the lessons learned in the past.

But: It's absurd to conclude that because public unions aren't working well that they can never work well. That's a good argument for total anarchy: the government isn't working as intended at the moment, and the mechanisms we built in to fix things when they go wrong are being kept out of reach -- therefore government can never work, so let's scrap it altogether.

Human organizations are messy, and very often testing solutions properly requires more time than the average human attention span can bother waiting for. But that just makes things difficult not impossible.

Take affirmative action, just as an example. 300 years of oppression and disenfranchisement left black Americans without self-sustaining communities, institutions and wealth to create a reliable path to social mobility through work. It wasn't just slavery, it was lack of home ownership, discriminatory lending practices, forced and then de facto segregation, targeted arbitrary law enforcement by police. We're still filling prisons with people for drug possession, while, eg, the three white guys who started the opiate epidemic were convicted and got community service. They're still paying for their grandkids college and study abroad and making sure they get cherry jobs, etc.

But they will seethe with "injustice" when their granddaughter didn't get into her first choice when she had the exact same GPA and SAT scores as a black girl who did get in. It will never occur to them that her clean record and her accumulated virtue was possible only because her life was without need or conflict.

I'm not saying Affirmative Action is the right answer to that problem. Any attempt to dispense justice across generations is problematic just based on our belief in the sovereignty of the individual.

The point is that we tried to solve a deep, 300+ year old problem by changing college admissions policies for like 30 years, then declared the problem simultaneously unsolvable and totally solved. For AA to be evaluated you'd need a century of data and oversight, simultaneous testing of different methods, robust evaluation, immunity from biannual political whim, and a broad cultural understanding that occasional failure is a necessary prerequisite for success, not proof that the whole thing is impossible.

Real solutions to big social problems take time, and it should be expected that a solution that produces desirable results -- like unions did in the first half of the 20th century when they helped create the America of broad wealth distribution that everyone wants to return to -- might eventually become corrupted and require reform -- an idea that should be built in to the process of keeping a democracy healthy.

The history of unions in America -- and the lasting successes we owe them -- ought to be sufficient evidence that not only can they work well again, their success is vital to our functioning capitalist democracy. Without them we end up with a government that, eg, celebrates and rewards removing wealth from the economy versus the most democratic method of wealth creation: labor.

TL/DR

I don't disagree that many unions have long since abandoned the role they were meant for and no longer serve their intended purpose. In the case of police and teachers' unions they seem to be doing more harm than good at the moment. But that's just another clear indicator (talk to a Walmart employee) that we need healthy unions more than ever -- even those of us (like me) who are "job creator" and would likely never benefit directly from a union.