Justice Samuel Alito, writing for the 6–3 majority, ruled that although the elements of a crime may not be considered "serious," sentence enhancements related to a defendant's prior record will bear on how the determination is made.

Prosecutors argued that the third required conviction was supplied by Rodriquez’s Washington state drug offenses.

Although none of the three drug convictions, on their own, was considered "serious," the second and third were repeat offenses and were punishable by ten-year sentences, which qualify as serious under ACCA.

"In sum, a straightforward application of the language of ACCA leads to the conclusion that the 'maximum term of imprisonment prescribed by law' in this case was 10 years.

Souter wrote that the text of ACCA was ambiguous, and in such cases the traditional rule of construction was to apply lenity in criminal statutes.