How does the Supreme Court's Blockburger test determine whether two charges are the same offense?

The Blockburger test is a standard established by the U.S. Supreme Court to determine whether two charges constitute the same offense under the Fifth Amendment protection against double jeopardy.

Rather than focusing on the underlying conduct or historical event, the test centers on the statutory elements of the crimes. According to the Supreme Court’s ruling in Blockburger v. United States (1932), the test asks whether each statutory provision requires proof of a fact that the other does not.1

If each charge necessitates proof of an element that the other does not, they are considered distinct offenses, and a defendant may be prosecuted for both. Conversely, if one crime is a lesser-included offense of the other—meaning it does not require proof of any additional fact beyond those required by the greater offense—the two are considered the same offense, and subsequent prosecution is barred. This approach differs significantly from many European legal systems, which often prohibit multiple trials for any offenses arising from the same factual situation.1