> American state run prisons and their surrounding ecosystem of courts, municipal govts, vendors, etc have much of the perverse incentives

Why do these institutions have perverse incentives? Is it because the voters reward high imprisonment rates because it creates the impression of safety?

Just to pick on one player, California prison workers’ union have immense political power. They have many members, and their self-interest is more prisons and more prisoners.

To go further, when you warehouse a bunch of people who can’t vote in a geographical area, you create a situation where few voters get to wield disproportionate power at all levels.

Also, if you warehouse people of child rearing age, then you’ll get fewer of that demographic in future elections (20 years from now).

I took a quick look at campaign financing laws in some other countries (UK, Germany, Canada, and Japan) and it seemed that the U.S. was the exception in allowing trade unions and industry associations to give money to politicians, along with unrestricted corporate contributions to political causes.

What would be considered bribery in many other countries is still legal in the U.S.

It is. The history as most voters perceive it is: crime was high and rising fast in the 70s and 80s, until we got "tough on crime" in the late 80s and early 90s, and crime finally started declining once all the criminals knew we'd be tough. So they conclude that the modern American justice system is what's causing crime to decline, and are concerned that being "soft on crime" would make crime start spiking again.

Don't get me wrong, I'm not a fan of mass incarceration, but you can see where the skepticism of reform comes from. It's impossible to overstate how bad things were perceived to be in the 90s.

Other commenter has good points too, but I primarily meant that there are still many many people (and entire rural towns!) making and dependent on the money involved. Even if the running of the prisons is "public".