Imprisonment was not always what it is today in the United States. However, a series of law enforcement actions and sentencing policy changes meant that there was a dramatic increase in the number of people going to prison.
The War on Drugs began in the 1980s, and since then, the total number of people who are incarcerated in U.S. prisons has risen from just 40,900 in 1980 to 452,964 in 2017. This jump is particularly important to address, because many of the people in prison are there for drug crimes.