In the United States, life imprisonment is the most severe punishment provided by law in states with no valid capital punishment statute, and second-most in those with a valid statute. According to a 2013 study, one of every 2,000 prison inhabitants of the U.S. were imprisoned for life as of 2012[update].[1]
American case law and penology literature divides life sentences into "determinate life sentences" or "indeterminate life sentences". The latter indicates the possibility of an abridged sentence, usually through the process of parole. For example, a sentence of "15 years to life" or "25 years to life" is called an "indeterminate life sentence", while a sentence of "life without the possibility of parole" or "life without parole" (LWOP) is called a "determinate life sentence".[2] West Virginia uses the unique terms "life with mercy" and "life without mercy", respectively, for these two categories.
The first category are "indeterminate" in that the true length of each prisoner's sentence is not determined up front by the sentencing court, but will depend upon when the prisoner can convince the state parole board of their rehabilitation after serving the minimum number of years provided for in the sentence. The second category are "determinate" in that it is expressly determined by the sentencing court up front that the prisoner will never have the chance to see the parole board. This means that criminals given a determinate life sentence will typically die in prison, without ever being released. If a life without parole sentence is imposed, executive branch government officials (usually the state governor) may have the power to grant a pardon, or to commute a sentence to time served, effectively ending the sentence early.
Many U.S. states offer parole after a decade or more has passed, but in California, people sentenced to life imprisonment can normally apply for parole after seven years.[3] Florida leads the country with nearly one quarter of its LWOP prisoners, more than California, New York and Texas combined.[4]