The first time I really understood the idea behind structured pleas was on the show the wire, at the end of the first season Avons lawyer advised him to do it;
It's like a turniket that stops the bleeding, it stalls the investigations at a certain point, so as to protect the higher ups.
If gott I was boss in the 40s-50s, it makes sense, but the commission case should have alerted him that he was living in a new world...