According to statistics released by the International Centre for Prison Studies, one in every 107 Americans is incarcerated. America, ostensibly the land of the free, is home to 5 percent of the world's population but 25 percent of its prisoners. The rapid growth of the nation's prison population, which began in the early 1980s, has been attributed to several factors. Chief among them are laws enacted in response to the nation's war on drugs, stricter enforcement of life sentences, the prosecution of juveniles in adult courts and expansion of the federal penal code.

At the Minimum

Judges rely on sentencing guidelines when imposing penalties for many crimes. They also take mitigating factors into consideration. However, if the crime is subject to the mandatory minimum sentencing law, the judge must impose the designated sentence or one that is harsher. The use of mandatory minimum sentencing laws expanded in the 1970s as the nation began its war on drugs. In the 1980s, Congress passed even harsher mandatory minimum sentences, primarily in connection with federal drug possession. Since then, these laws have also been applied to sex and gang-related crimes. Mandatory minimum sentences have greatly contributed to the rise in prison populations.

Impossibility of Parole

A life sentence didn't always equate to spending life in prison. Federal prisoners who received life sentences once were generally given their first parole review after 15 years. This lenient attitude toward life sentences changed, however, when the Supreme Court initiated a ban on the death penalty in 1972. In response to that ruling, many states began utilizing already established but rarely used life-without-possibility-of-parole sentencing. Since the 1970s, the federal government and the states of Illinois, Iowa, Louisiana, Pennsylvania and South Dakota have eliminated parole altogether. As of 2012, nearly 160,000 Americans are serving life in prison.

You're Not a Kid Anymore

For more than 80 years, the American justice system made a distinction between juvenile and adult crime, emphasizing rehabilitation, counseling and training for those considered too young to be held completely responsible for their actions. A dramatic rise in crime, particularly violent crime, among young people in the late 1980s led to public support for treating older juveniles as adults and transferring juvenile criminal cases to adult courts. Juvenile offenders tried as adults are more likely to receive prison sentences in adult correctional facilities. In the past 10 years, the number of people under 18 serving time in adult prisons has more than doubled. On an average day in 2010, 9,855 juveniles were incarcerated in adult correctional facilities.

Fifteen-Hundred Fold Increase

When the Constitution was finalized, it listed three federal crimes -- treason, piracy and counterfeiting. Since then, the number of acts considered federal crimes has increased to 4,500, a 1,500-fold increase. More importantly, there has been a significant decrease in laws written that require proof of intent to be convicted of a crime. Between 2000 and 2010, more than 780,000 people were convicted of federal crimes and received prison sentences ranging from up to a year for a misdemeanor to multiples of 10 years for a felony.

No Win Drug War

While few Americans opposed the justice system's tougher approach to dealing with the nation's illegal drug problem, the last three decades have seen the war on drugs evolve into the war on nonviolent drug-related crime. In 2011, nonviolent drug offenders made up 25 percent of the nation's prison population. In that same year, one in every 28 children had a parent in prison and two-thirds of these parents were incarcerated for non-violent crimes. (See Reference 9)