What Is Double Jeopardy?
The constitutional rule that the government cannot try you twice for the same crime after you have been acquitted or convicted. Once the criminal case is over, it's over.
Quick Answer
The constitutional rule that the government cannot try you twice for the same crime after you have been acquitted or convicted. Once the criminal case is over, it's over.
Full Explanation
The Double Jeopardy Clause of the Fifth Amendment says that no person shall 'be subject for the same offence to be twice put in jeopardy of life or limb.' The clause protects against three things: a second prosecution after acquittal, a second prosecution after conviction, and multiple punishments for the same offense in the same proceeding.
Jeopardy 'attaches' at a specific moment — for jury trials, when the jury is sworn in; for bench trials, when the first witness is sworn in. Before that point, the case can be dismissed and re-filed without double jeopardy concerns.
The 'same offense' question is analyzed under the Blockburger test (from Blockburger v. United States, 1932): two offenses are the same unless each requires proof of a fact that the other does not. This is how the government can charge someone with both robbery and assault arising from the same incident — each crime has a unique element.
The dual sovereignty doctrine is a major exception: because the federal government and state governments are separate sovereigns, each can prosecute the same conduct without violating double jeopardy. This is why, after the state acquitted officers in the Rodney King case in 1992, the federal government was able to prosecute them for civil rights violations.
Importantly, a not-guilty verdict is absolutely final — there is no 'appeal' by the prosecution from an acquittal.
Real-World Example
O.J. Simpson was acquitted of murder in his 1995 criminal trial. He could not be retried for murder — double jeopardy barred a second prosecution. However, the civil lawsuit by the victims' families was not barred because civil cases are not 'jeopardy' under the criminal law clause.
In the Rodney King case, the state prosecution ended in acquittal, but federal prosecutors charged the officers with federal civil rights violations. The Supreme Court upheld this in similar cases under the dual sovereignty doctrine.
Why It Matters for Law Students
Double jeopardy is a fundamental protection in criminal procedure and a frequent bar exam topic. It illustrates the principle that the government, with all its resources, should only get one fair shot at conviction. Understanding when jeopardy attaches, the Blockburger test, and the dual sovereignty exception are all essential for criminal procedure.