The percentage (40%) is arbitrary. I know that there are way too many prisoners languishing in jail doing nobody any good because of draconian anti-drug laws enacted when Nelson Rockefeller was Governor of New York. For some reason politicians are unable propose undoing the adverse consequences of what they create. It is easy for a politician to been viewed as a supporter of law and order, and then lock up 12-year olds for life because of getting caught smoking pot several times. What makes a politician great, in my opinion, is the ability to legislate fairly and as needed, in spite of the public's fairly to appreciate the circumstances.
We need to depopulate our prisons. The cost to the public in a variety of ways is outrageously high and is ruining our state and country. It costs money for the persons outside of jail to maintain the ever-increasing population inside of jail, and to this burden you have to add the increasing number of persons in economic jail, unable to obtain meaningful employment and pay meaningful taxes. Thus, the taxes fall on an ever-decreasing number of people in New York to pay for the poor, the poor sick, the incarcerated, the underemployed, the unemployed and numerous others. We should start sharing the load by getting vast numbers of harmless people out of jail, and create new and improved products and services with consequent new jobs and business opportunities to build our economy in New York.
As NYS Attorney General, I would look for legal ways to reduce the prison population (including determinations that some prosecutions were faulty or that sentences were excessive under various Constitutional provisions) and probably achieve more success than the legislators who talk about a legislative solution.