Utilitarianism is the philosophic theory that claims that the consequences of human actions are what counts when evaluating their value as individuals, and that each action should contribute for the greatest happiness for the greatest number of people.
In relation to jail, the theory states that the evil of punishment is justify only when it’s useful for the good of the community. Those uses may be prevent or reduce crime, protect the public from certain offenders, rehabilitate the inmate, and keep others from committing those crimes. In regards to utilitarianism, it is morally wrong to disobey any law, since this action itself is harmful for the smooth run of society. This approach goes hand to hand with Liberalism.
However, there is a series of critiques aimed to this method. First of all, if it were sound, we would expect really dangerous people to be in jail, and that offenders were deterred of committing new crimes after their sentence is done. We would also anticipate a similar rate of female and male offenders, and a roughly similar number of black, First Nations, and white people in jail.
But if we study these places we find that this is not particularly true. For example, in Canada, only 25% of the inmates are female. Overall, 33 years of age is the average age upon admission; nevertheless, the average age for aboriginal inmates is 29 years old; in addition, 25% of the male inmates and 40% of females are First Nations. In 2008, 21.3% of the jail population was prescribed with medication regarding mental issues; in British Columbia, 30% of the offenders have been diagnosed with disorders, and 80% of the female population has received a psychiatric diagnosis.