Bill was charged with shoplifting and pleaded not guilty on the advice of his counsel, since the evidence wasn't all that decisive. The members of the jury also were indecisive and ultimately unable to reach a unanimous verdict, commonly referred to as a "hung jury," resulting in a mistrial. A few weeks later, however, Bill is charged again for the same crime after the prosecution obtains surveillance footage they claim proves his guilt.

Bill is perplexed, believing his constitutional rights have been violated. But have they? More to the point, when does double jeopardy "attach" within the context of the Constitution?

Definition of Double Jeopardy

The Fifth Amendment to the U. S. Constitution states: "No person shall ... be subject for the same offense to be twice put in jeopardy of life or limb." As you can imagine, this guarantee in the Bill of Rights is important because it prevents different prosecutors from using the same conduct or incident to continually prosecute you until they come up with a conviction.

But it's important to understand the nuances of this right, since it's not always as clear as it may seem.

When Double Jeopardy Attaches: Overview

Double jeopardy protections in the U.S. Constitution keep criminal defendants from being prosecuted twice for the same offense. But the protection does not “attach” itself to a case immediately when a defendant is charged, nor does it necessarily end upon conviction.

Once someone is charged with a crime, jeopardy attaches at the following stages:

• When the jury is sworn;
• When the first witness is sworn (for cases tried by a judge without a jury);
• When the court first hears evidence in a juvenile proceeding; or
• When the court accepts a plea agreement between a defendant and a prosecutor.

When Jeopardy Ends in Favor of the Defendant

Once jeopardy has attached and the defendant is found innocent, the government can't detain them for additional court proceedings on the same issue. Jeopardy therefore “ends” at the following exonerating stages:

• After a jury’s verdict of acquittal;
• After a trial court judge grants a dismissal, unless the judge abused their discretion;
• After a successful post-conviction appeal; or
• After a mistrial (only if the judge dismisses the case).

Successful appeals and mistrials, while both “exonerating proceedings,” deserve further attention, as they present a wide range of results.

When Double Jeopardy Attaches: Successful Appeals

Ironically, a successful appeal may necessitate a new trial, again placing a convicted offender in jeopardy. If a case is reversed on appeal, jeopardy will not attach until the court reaches a final judgment upon retrial. The prime exception to this rule is reversal for insufficient evidence, which permanently frees the defendant.

As the Supreme Court found in U.S. v. Perez, retrials are allowed because double jeopardy applies only to final judgments. Judgments based on reversible errors are not final judgments protected by the Fifth Amendment. Examples of these reversible errors are

• Instructing the jury on law inapplicable to the case;
• Applying the wrong legal standard;
• Permitting seriously improper attorney argument;
• Improperly admitting or excluding evidence, such as evidence without foundation;
• Juror misconduct at material stages of the trial;
• Judge’s abuse of discretion “outside the bounds of reasonableness;”
• The law applied was later found to be unconstitutional;
• Recently discovered evidence that would have probably changed the verdict; and
• Ineffective assistance of counsel.

Mistrials and Double Jeopardy

Mistrials don’t necessarily invoke double jeopardy protections unless the trial judge weighs the reasoning for the mistrial and rightly dismisses the case. Deadlocked jurors who are honestly split in their opinions can lead to retrials if “manifest necessity” demands a retrial.

Mistrials caused by prosecutorial conduct are obviously protected by the double jeopardy rule, and the charges remain dismissed through all jurisdictions. Conversely, double jeopardy doesn't attach when the defendant intentionally causes a mistrial, and they can be subject to a new trial.

Get Help Understanding the Concept of Double Jeopardy

Double jeopardy protection is a complex area of criminal law. If you’re being investigated for a crime that was similar to one for which you've already served jail time, you'll want to understand whether double jeopardy attaches. If you want to know if you’re being unfairly prosecuted for the same conduct, you can meet with a local criminal defense attorney to discuss your case.