Shepard v. US, Supreme Court of the United States, Justice Souter, March 7, 2005 [holding that in making certain sentencing determinations, judges are confined to information in the charging document, in the terms of any plea agreement terms, or admissions by the defendant made to the trial judge, but cannot review other sources, such as police reports]. Excerpt:

Title 18 U.S.C. § 924(e) (2000 ed. and Supp. II), popularly known as the Armed Career Criminal Act (ACCA), mandates a minimum 15-year prison sentence for anyone possessing a firearm after three prior convictions for serious drug offenses or violent felonies. The Act makes burglary a violent felony only if committed in a building or enclosed space ("generic burglary"), not in a boat or motor vehicle. In Taylor v. United States, 495 U.S. 575 (1990), we held that a court sentencing under the ACCA could look to statutory elements, charging documents, and jury instructions to determine whether an earlier conviction after trial was for generic burglary. The question here is whether a sentencing court can look to police reports or complaint applications to determine whether an earlier guilty plea necessarily admitted, and supported a conviction for, generic burglary. We hold that it may not, and that a later court determining the character of an admittted burglary is generally limited to examining the statutory definition, charging document, written plea agreement, transcript of plea colloquy, and any explicit factual finding by the trial judge to which the defendant assented.

Read the full text of the opinion [PDF]. Reported in JURIST's Paper Chase here.