Rarely do courts in the United States overturn sentences on Eighth Amendment grounds. But, in a recent decision, a federal appeals court holds that a mandatory minimum sentence constitutes cruel and unusual punishment under the Eighth Amendment:

The Eighth Amendment prohibits the infliction of “cruel and unusual punishments.” U.S. CONST. amend. VIII. Central to this prohibition is the requirement that the punishment for crime “be graduated and proportioned to the offense.” Graham v. Florida, 560 U.S. 48, 59 (2010). However, this proportionality principle is narrow, and it only forbids “extreme sentences that are grossly disproportionate tothe crime.” Harmelin v. Michigan, 501 U.S. 957, 1001 (1991) (Kennedy, J., concurring in part and concurring in judgment). There are two types of Eighth Amendment challenges to sentences: 1) challenges to sentences as applied to an individual defendant based on “all the circumstances in a particular case” and 2) categorical challenges to sentences imposed based on the nature of the offense or the “characteristics of the offender.” See Graham, 560 U.S. at 59–61. Slough, Liberty and Heard assert their sentences are disproportionate both as applied to their situations individually and categorically to all defendants who have discharged government-issued weapons in a war zone. We begin by addressing the as-applied challenges.

When addressing an as-applied challenge, courts begin “by comparing the gravity of the offense and the severity of the sentence” based on “all of the circumstances of the case.” Id. at 59, 60. When engaging in this comparison, courts are to give “substantial deference to the broad authority that legislatures necessarily possess in determining the types and limits of punishments for crimes.” Solem v. Helm, 463 U.S. 277, 290 (1983). Also, the imposition of a severe mandatory sentence does not in itself make a sentence unconstitutional. See Harmelin, 501 U.S. 994 (“Severe, mandatory penalties may be cruel, but they are not unusual in the constitutional sense.”); see also id. at 1006–07 (Kennedy, J., concurring in part and concurring in judgment) (“We have never invalidated a penalty mandated by a legislature based only on the length of sentence . . . .”). Thus, courts should be “reluctant to review legislatively mandated terms of imprisonment,” and “successful challenges to the proportionality of particular sentences should be exceedingly rare.” Hutto v. Davis, 454 U.S. 370, 374 (1982) (per curiam). However, the unusual circumstances of this case make it one of those “exceedingly rare” instances. 

D.C. CIRCUIT COURT OF APPEALS.  The opinion deals with a lot of issues. The Eighth Amendment analysis begins at page 69.