What's the minimum time that an indeterminate life sentence may have
in the US?
In addition to the federal criminal code (Title 18 of the United States Code) and every U.S. state has criminal offenses set forth in a criminal code. The federal government and many U.S. states also have criminal offenses that are set forth in statutes outside the primary criminal code for the jurisdiction.
Not every U.S. state has indeterminate sentencing, and the current trend is away from indeterminate sentencing, but in jurisdictions that do, there can be great variation. Some jurisdictions use indeterminate sentencing for almost all felony offenses, while others use it only for exceptionally serious offenses like rape and murder.
The minimum sentence in an indeterminate sentence imposed upon a single individual is the time at which a person becomes eligible for parole.
Typically, parole boards do not exist at the local government level, so typically, indeterminate sentencing is not used for misdemeanor offenses.
Usually, incarceration in a state prison is reserved for sentences of one year or more, so usually, the minimum range of an indeterminate sentence can be as short as one year.
In practice, an indeterminate sentence can also be reduced for time served prior to conviction, and sometimes, but not always, it can be reduced for what is known as "good time" which is an administrative sentence reduction granted by prison officials when an inmate behaves well and meet institutional guidelines.
So, an indeterminate sentence, for example, of 1-5 year could be reduced to a matter of months before a defendant is eligible for parole in some circumstances.
In Colorado, for example, most crimes a punishable by determinate sentences, but sex offenses are punished by indeterminate sentences, with a sentence of two years to life, for example, being a common sentence for a comparatively low level sex offense, such as felony unlawful sexual conduct or internet luring of a child. See, e.g., Colorado Revised Statues §§ 18-1.3-401, 18-1.3-1003, 18-1.3-1004, 18-3-306, and 18-3-404.