Growth in the lifer population has helped keep the prison population high.

From a 1973 benchmark, the prison population had quintupled to its current level of roughly 10,000 by 1993. One might have expected the prison population to begin falling as crime rates fell through the 90s and into this century. Yet, the prison population has remained fairly stable since 1993. The population committed for the most serious crimes (life sentences or sentences longer than 20 years) has continued to rise steadily, explaining much (but not all) of the continued high number of prisoners.

Legislative penalty changes contributed only modestly to the prison population run-up.

Several observations (in this post) suggest that the role of legislative enactments in the state prison population increase was limited. Non-legislative factors that could explain the rise include, of course, the stunning rise in crime itself and discretionary responses to that rise by communities, law enforcement and the courts. However, parole board release decisions do not seem to be a likely factor.

The Massachusetts Legislature regularly enacts criminal penalty increases.

Legislators respond with the tools that they have to public concerns and to troubling events. One can see, in the list of major criminal law enactments in this post, the history of punitive responses to recurring waves of legitimate public concern about drunk driving, drugs, guns, domestic violence, youth violence, sex offenses and crimes against the elderly.