The role of juries in civil and criminal cases

The jury is one of the most distinctive features of the U.S. legal system. Most countries either don't use juries at all or use them only in criminal cases. The U.S. uses them in both, and the right to a jury [trial](/insights/glossary/trial) is built into the Constitution.

This lesson explains what juries actually do, how jurors are selected, how juries deliberate, and why most cases never see one.

The basic role

A jury's job is simple to state and hard to do well: decide the facts.

The judge is in charge of the law: what the legal standards are, what evidence is admissible, what the jury has to decide. The jury is in charge of the facts: what actually happened, who's telling the truth, what the evidence really shows.

That division explains a lot of what happens in a trial:

The judge can throw out a case before it reaches the jury (summary [judgment](/insights/glossary/judgment)) if there's no genuine fact dispute. If the case can be decided on undisputed facts, the jury has nothing to do.
The judge decides what evidence the jury hears. Inadmissible evidence (hearsay, irrelevant material, etc.) gets excluded outside the jury's presence.
After hearing the evidence, the jury applies the law (as the judge explains it) to the facts they find. The result is a verdict.
The judge enters a final judgment based on the verdict.

If the jury reaches an unreasonable verdict, the judge has limited power to override it (a "judgment notwithstanding the verdict"): but appellate courts give juries lots of deference. Reversing a jury verdict is rare.

Constitutional jury rights

Two amendments protect jury rights:

The Sixth Amendment guarantees the right to a jury in criminal cases. This applies to "serious" criminal offenses: meaning anything punishable by more than six months in jail. Petty offenses don't trigger the right.

The Seventh Amendment guarantees the right to a jury in civil cases at common law where the amount in dispute is more than $20 in federal court. (The $20 figure is from the 1791 Constitution and has never been adjusted.) This covers most traditional civil claims: contracts, torts, property: but not all (equity claims like injunctions don't always trigger it).

State constitutions echo these protections, often with their own variations. Most state civil cases above modest dollar amounts also carry jury rights.

When juries actually decide cases

Despite the constitutional right, most cases don't reach a jury. Several reasons:

Most cases settle. Estimates put civil settlements at 90%+ of filed cases. No trial means no jury.
Many cases get decided on summary judgment. When there's no genuine factual dispute, the judge decides on the law without sending it to the jury.
Some cases get bench-tried. Even when the right exists, both parties can waive it. Bench trials are often faster, less risky, and useful in technical cases where the judge's expertise is more useful than the jury's common sense.
Equity claims often have no jury right. Cases asking for injunctions, specific performance, or other equitable remedies historically had no jury right and often still don't.

A typical civil litigator might try one or two jury cases a year: out of dozens of cases on their docket.

How jurors get picked

The jury selection process: sometimes called voir dire: works like this:

Jury pool. Names are drawn at random from voter rolls, driver's licenses, or both. People in the pool get summoned to come to the courthouse on a specific day.
Jury panel. From the pool, a smaller panel is sent to a specific courtroom for a specific case.
Voir dire. The judge and the lawyers question the panel about their backgrounds, biases, and ability to be fair. Common questions: have you been involved in similar litigation? Do you know any of the parties? Have you formed an opinion based on pre-trial publicity?
Strikes. Each side can strike potential jurors: - For cause. Unlimited number: used when a juror clearly can't be impartial (relative of a party, expressed bias, etc.). - Peremptory. A limited number: strikes a juror without explaining why. Limited by Supreme Court rulings against using peremptory strikes based on race or gender.
Final jury. After strikes, the remaining jurors form the jury for the case. Federal civil juries are typically 6-12. Federal criminal juries are 12. State sizes vary.

Sometimes alternates are also selected: extra jurors who sit through the trial in case a regular juror can't continue. They only deliberate if a regular juror gets dismissed.

During the trial

Jurors are essentially audience members during the trial. They listen, watch, take notes (in jurisdictions that allow it), and follow the judge's instructions about what they can and can't do.

What they can't do during a trial:

Discuss the case with anyone, including each other (until deliberation)
Research the case online or visit the scene
Talk to the parties, lawyers, witnesses
Decide anything before all the evidence is in

These rules are taken seriously. A juror who looks up the case online or talks about it on social media can cause a mistrial.

Deliberation

After closing arguments and jury instructions, the jury retires to the jury room to deliberate. They:

Pick a foreperson (or are assigned one)
Discuss the evidence
Vote on the verdict
Sometimes ask the judge questions if they get stuck

Deliberation can take an hour or weeks, depending on the case. Some cases produce verdicts in 30 minutes; some lock up the jury for days.

In federal civil cases, the verdict has to be unanimous unless the parties agree otherwise. In federal criminal cases, unanimity is required. State systems vary: some allow non-unanimous verdicts in civil cases, though Louisiana and Oregon recently changed their criminal rules after the Supreme Court ruled non-unanimous criminal verdicts unconstitutional.

What happens if the jury can't agree

A jury that can't reach a verdict is "hung." The judge usually instructs them to keep trying, sometimes with a special instruction (the "Allen charge") that encourages them to listen to each other.

If they still can't agree, the judge declares a mistrial. The case can be retried with a new jury: though many cases settle after a mistrial because both sides have just learned something about how juries see the evidence.

What jurors think about

A persistent body of research has tried to figure out how juries actually decide cases. Some findings:

Juries take their job seriously. The "they decide based on emotion / who's prettier" stereotype is mostly wrong.
Juries deliberate carefully, especially in serious cases. They review evidence, talk through arguments, vote multiple times.
Juries do bring lay common sense: sometimes catching legal subtleties lawyers missed, sometimes missing legal subtleties lawyers thought were obvious.
Pretrial attitudes matter, especially in civil cases. Jurors who came in skeptical of large damages awards are hard to flip.
The order in which jurors talk in deliberation matters more than the order in which witnesses testified at trial.

Why the jury system survives

Critics point out that juries are slow, expensive, sometimes wrong, and sometimes inconsistent. So why keep them?

Several reasons:

Democratic legitimacy. A jury verdict represents the conscience of the community, not just the opinion of one elite official.
Check on government. Especially in criminal cases, the requirement of jury unanimity is a real protection against overzealous prosecution.
Lay common sense. Juries sometimes catch problems with cases that lawyers miss because they're too close to the case.
Constitutional guarantee. Changing this would require constitutional amendment.
Acceptance of outcomes. Parties may accept a jury verdict more readily than a judge's ruling because it came from peers.

The jury system is far from perfect. But its imperfections are familiar, well-documented, and tolerated as part of the price of a system that gives ordinary citizens a real role in deciding their society's most contested questions.

This lesson is research and educational information, not legal advice. If you've received a jury summons, follow the instructions on the summons exactly: the deadlines and requirements vary by court.