In the case of Reginald Shepard v. United States, 2004, the Supreme Court was asked to determine whether a prior conviction can be considered a violent felony under the Armed Career Criminal Act (ACCA) if it does not explicitly involve conduct that presents serious potential risk of physical injury to another. The ACCA imposes a mandatory minimum sentence for individuals convicted of being felons in possession of firearms who have three or more previous convictions for violent felonies. Reginald Shepard had pleaded guilty to being a felon in possession and argued that his four prior convictions were not "violent" as defined by ACCA because they involved burglary offenses where no one was present at home during commissioning of crime. The court ruled in favor of Shepard stating that only those crimes which inherently involve potential violence should count towards enhancing sentences under ACCA; hence, courts cannot look into police reports or complaint applications to determine nature and severity but must rely on statutory definitions or charging documents alone.

In the dissenting opinion for Shepard v. United States, Justice O'Connor, joined by Chief Justice Rehnquist and Justices Scalia and Thomas, argued that the majority's decision was inconsistent with Congress' intent in enacting the Armed Career Criminal Act (ACCA). They believed that a sentencing court should be able to look at reliable judicial records of prior convictions to determine whether they qualify as violent felonies under ACCA. The dissenters disagreed with the majority's view that only charging documents or jury instructions can provide this information. Instead, they contended other sources like plea colloquy transcripts or written plea agreements could also offer clear evidence about a defendant’s past crimes without violating his Sixth Amendment rights. In their view, limiting courts’ ability to consider these materials would undermine ACCA’s purpose of imposing harsher sentences on repeat violent offenders.