The police union in my city, in a state that borders Canada and fought against slavery, was founded in 1915. I'm guessing they would be surprised to learn that they are a "modern invention" that was from "slave catching" (I guess they do time travel?) and "bounty hunting services". I'm not even sure how you can say something is both a "modern invention" and the "output of slave catching". There's nothing modern about them and being the "output of slave catching" makes them definitionally not "modern".

Police unions act just like every other union does: in the interests of their members.

Unions are illegal in lots of the world. Federal public sector unions weren't legal in the US until the 1960s. Did the fact that they were illegal in 1965 have any bearing on whether or not they should be allowed? Does the fact that something is illegal in the US have any bearing on whether or not Japan should allow it?

> Police unions aren’t labor unions

I'd really like to know what kind of tangled logic it requires to believe that.

Regardless, police unions aren't the only example of unions who have worked against the benefit of everyone else but themselves. I only used them as an example because I didn't think anyone here would argue disagree that it's had negative outcomes.

What I didn't expect was to find someone arguing that a union wasn't a union. It doesn't matter if it's legal in other places, it's legal in the US. Just because Japan has made police _unions_ illegal doesn't make an US police _union_ not a union.