In a trial, the case in chief is the phase where a party presents its main evidence and witness testimony to prove its claims or defenses. It’s the substantive middle of the trial: jury selection and opening statements come before it, closing arguments and deliberation come after, and the outcome is largely decided by what happens during it. The plaintiff or prosecution presents its case in chief first, and once that party rests, the defense gets its own turn.
Where the Case in Chief Fits in a Trial
A trial follows a predictable order. After a jury is selected and both sides give opening statements, the party carrying the burden of proof goes first: the plaintiff in a civil suit, the prosecution in a criminal one. That party calls witnesses, introduces documents and physical evidence, and builds the factual story supporting its legal claims.
When it finishes, it formally “rests.” The opposing side then has the chance to present its own case in chief. After both sides rest, the trial may move into rebuttal and, occasionally, surrebuttal before closing arguments. A case in chief is not a single hearing or moment. In complex trials it can run for days or weeks, depending on how much evidence a party needs to present.
How the Burden of Proof Shapes It
The burden a party carries controls how its case in chief looks. A heavier burden means more witnesses, more corroborating evidence, and a longer, more methodical presentation.
Civil plaintiffs must prove their claims by a preponderance of the evidence — more likely true than not. Their case in chief is built to clear that threshold on every element of the claim.
Criminal prosecutors carry a much heavier load: proof beyond a reasonable doubt. In In re Winship, the Supreme Court held that the Due Process Clause requires this standard for every fact necessary to establish the charged crime, making it a constitutional guarantee.1Cornell Law School LII. In the Matter of Samuel Winship, Appellant Because that standard demands near-certainty, a prosecution case in chief tends to layer forensic evidence, eyewitness accounts, and documentary proof to close off avenues of reasonable doubt.
What Gets Presented
The evidence in a case in chief generally falls into three categories, and the presenting party controls the order and emphasis.
Physical Exhibits
Physical exhibits include documents, photographs, contracts, medical records, weapons, DNA samples, and other tangible items. Before an exhibit reaches the jury, the party offering it must authenticate it. Under the Federal Rules of Evidence, authentication requires evidence sufficient to support a finding that the item is what its proponent claims it is.2Legal Information Institute. Federal Rules of Evidence Rule 901 – Authenticating or Identifying Evidence
For some items — seized drugs, blood samples — authentication also requires a chain of custody: an account of who handled the item and where it was stored from collection through trial. A broken chain gives the opposing side an opening to argue the evidence may have been contaminated or tampered with.
Fact Witnesses
Fact witnesses testify about events they personally saw or experienced: the bystander to a crash, the employee at a meeting, the neighbor who heard an argument. Their credibility is tested on cross-examination, which under Rule 611 is limited to the subject matter of direct examination and matters affecting credibility, though the court can allow broader questioning at its discretion.3Legal Information Institute. Federal Rules of Evidence Rule 611 – Mode and Order of Examining Witnesses and Presenting Evidence What a party covers on direct during its case in chief therefore controls how far the other side can push on cross.
Either party can also ask the court to sequester witnesses, ordering them out of the courtroom so they cannot hear each other testify. The court must grant the request, though the rule contains exceptions for a party who is a natural person, a designated corporate representative, and anyone essential to presenting a claim or defense.4Legal Information Institute. Federal Rules of Evidence Rule 615 – Excluding Witnesses
Expert Witnesses
Expert witnesses offer opinions based on specialized knowledge rather than firsthand observation: a medical expert on injury effects, a forensic accountant tracing funds, an accident reconstructionist explaining a collision.
Expert testimony faces an extra gatekeeping step. Under Daubert v. Merrell Dow Pharmaceuticals, the trial judge must evaluate whether an expert’s methodology is scientifically valid and relevant before letting the testimony reach the jury.5Cornell Law School LII. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 Rule 702 also requires that expert testimony be based on sufficient facts, reliable methods, and a reliable application of those methods to the case.6Legal Information Institute. Federal Rules of Evidence Rule 702 – Testimony by Expert Witnesses Weak expert testimony can be excluded before the case in chief begins, which is why Daubert challenges are usually filed well before trial.
The Goal: A Prima Facie Case
The point of a case in chief is to establish a prima facie case — enough evidence on every required element that a reasonable factfinder could rule in the presenting party’s favor. In a personal injury lawsuit, that means offering some evidence of duty, breach, causation, and damages. Skip an element and the case fails, no matter how strong the evidence on the others.
What Happens When a Party Rests
When a party finishes and announces it “rests,” the opposing side can immediately ask the court to end the case, arguing that no reasonable jury could rule for the party that just presented.
In civil trials, that request is a motion for judgment as a matter of law under Federal Rule of Civil Procedure 50. The court grants it when a reasonable jury would not have a legally sufficient evidentiary basis to find for the party on a given issue.7Legal Information Institute. Federal Rules of Civil Procedure Rule 50 – Judgment as a Matter of Law in a Jury Trial In criminal trials, the equivalent is a motion for judgment of acquittal under Federal Rule of Criminal Procedure 29, which requires the court to enter an acquittal for any offense where the evidence is insufficient to sustain a conviction.8Legal Information Institute. Federal Rules of Criminal Procedure Rule 29 – Motion for a Judgment of Acquittal
These motions are common but rarely granted. The court views the evidence in the light most favorable to the party that just rested, which is a deliberately high bar. Still, a case in chief that leaves a required element unsupported can end here, before the other side puts on any evidence at all.
The Defense’s Case in Chief
Once the plaintiff or prosecution rests and any motion is denied, the defense may present its own case in chief. This is an opportunity, not a requirement. In a criminal trial the defendant has no duty to present evidence at all; the burden never shifts, and the defense can argue only that the prosecution failed to meet it.
When the defense does present, it might call alibi witnesses, introduce contradictory physical evidence, offer character testimony, or put on its own experts. The same evidentiary rules apply: witnesses face cross-examination, exhibits must be authenticated, and expert testimony must pass the reliability standard. When the defense rests, the other side can raise the same motions in reverse, aimed at any affirmative claims the defense had to prove (such as a civil counterclaim).
Rebuttal and Surrebuttal
After the defense rests, the plaintiff or prosecution may offer rebuttal evidence. Rebuttal is narrower than a case in chief. It addresses only new matters raised by the defense; it cannot be used to introduce evidence a party forgot the first time or to repeat its strongest points.
Some courts allow surrebuttal, letting the defense answer new material raised during rebuttal. It is rare and tightly limited to those specific issues.
A Criminal-Trial Limit: The Confrontation Clause
In criminal cases, the Sixth Amendment gives the defendant the right to confront witnesses testifying against them. In Crawford v. Washington, the Supreme Court held that testimonial statements — such as statements made during police interrogations — cannot be admitted against a defendant unless the witness is available for cross-examination or the defendant had a prior opportunity to cross-examine them.9Cornell Law School LII. Crawford v. Washington (02-9410)
That shapes how a prosecution case in chief gets built. A statement from a witness who refuses to appear or cannot be located may be excluded entirely, however powerful it would otherwise be. Prosecutors have to plan around it, making sure key testimonial evidence comes from witnesses who will take the stand.