I learned from the documentary 13th (which I HIGHLY recommend) that something like 97% of people incarcerated in the US have never had a trial, because they're persuaded, manipulated or otherwise cajoled into making plea bargains.
What this means is that the US has replaced its common-law adversarial criminal justice system, with something completely different. Almost completely, and with very little debate. No referendum, no constitutional amendments. The old one sticks around for occasional ceremonial use.
It would be interesting to understand better why. My theory is that part of it is to do with rising standards of criminal trials. IIRC the average murderer went from arrest to dead in something like a month, 1950s. Most had no appeals. Certainly no expert witnesses to explain the DNA evidence to the jury. Today the default seems to be decades of appeals, thousands of hours of lawyer-time. That doesn't scale.
Said my lawyer when I had to deal with stacked charges leading to years of incarceration for the mildest of subjective crimes.
Why? So they could have me plead guilty.
Never happened. Fuck the system.