criminal procedure


Criminal procedure deals with the set of rules governing the series of proceedings through which the government enforces substantive criminal law. Municipalities, states, and the federal government each have their own criminal codes, defining types of conduct that constitute crimesTitle 18 of the U.S. Code outlines all federal crimes. Typically, federal crimes deal with activities that either extend beyond state boundaries or directly impact federal interests.


Federal prosecutions follow the Federal Rules of Criminal Procedure, cited as Fed. R. Crim. P., which the U.S. Supreme Court promulgated and Congress passed. The Federal Rules outline the procedure for conducting federal criminal trials. The Federal Rules incorporate and expound upon all guarantees included within the U.S. Constitution's Bill of Rights, such as the guarantee to due process and equal protection, the right to legal counselthe right to confront witnesses, the right to a jury trial, and the right to not testify against oneself.


State prosecutions follow the criminal procedure code of the individual state. Although every state has its own criminal procedure code, many states choose to mimic the Federal Rules. State procedural rules may offer greater protection to a defendant in a criminal trial than the U.S. Constitution or the Federal Rules, but may not offer less protection than guaranteed by the U.S. Constitution.

Investigatory and Accusatory Police Procedure

The U.S. Constitution, the Federal Rules, state and local rules, and court interpretation of these documents not only set out how trials are run but also prescribe the procedures that law enforcement agencies must follow. Should an officer fail to abide by the proper procedure, the trial court may suppress evidence obtained in violation of proper procedure, which could even lead to the suspect's acquittal. 

Law enforcement agencies are limited in their abilities well before an arrest is made. A portion of the criminal procedure process deals with an officers’ ability to stop individuals, search them or their properties, and seize any incriminating evidence the officer finds. This pre-arrest investigation is limited by the FourthFifthSixth, and Fourteenth Amendments.

Fourth Amendment

The Fourth Amendment protects individuals from unreasonable searches and seizures. As the Supreme Court explained in Mapp v. Ohio, 367 U.S. 643 (1961), evidence obtained by searches and seizures in violation of the U.S. Constitution is inadmissible in a criminal trial. In order to avoid illegally searching or seizing the property of a suspect, law enforcement personnel typically obtain search warrants. To obtain a search warrant, law enforcement must show probable cause, must support the showing by oath or affirmation, and must describe in particularity the place they will search and the items they will seize. 

Just as criminal procedure limits what is a reasonable search, it also specifies what constitutes a reasonable interrogation. In Miranda v. Arizona, 384 U.S. 436 (1966), the Supreme Court held that police must make defendants aware of their rights prior to the defendant making any statements, provided the government intends to use those statements as evidence against the defendant. The Fifth Amendment and the Sixth Amendment require law enforcement to ensure that defendants understand their right to remain silent and their right to have an attorney present during the interrogation.

The Fourteenth Amendment applies all the aforementioned substantive due process rights to state criminal defendants.

Pre-Trial Procedure

Right to a Speedy Trial

The Sixth Amendment to the U.S. Constitution guarantees criminal defendants the right to a speedy trial. Consequently, prosecutors cannot wait an inordinate amount of time before filing charges or proceeding with the prosecution after filing charges. Under the Speedy Trial Act, which Congress passed to clarify the speedy trial guarantee, a trial must begin within 70 days of the prosecutor filing the indictment.

Voir Dire

The Sixth Amendment also guarantees the right to a public trial by an impartial jury of one's peers. One manner in which the criminal justice system attempts to provide for an impartial jury is by permitting both sides to use peremptory challenges during jury selection. If a party exercises a peremptory challenge against a prospective juror, then the court must excuse that juror from the panel. These challenges occur during jury voir dire, and are meant to root out bias. While neither the prosecution nor the defendant needs to explain their reasons for a challenge, not every challenge is permissible. As the Supreme Court explained in Batson v. Kentucky, 476 U.S. 79 (1986), and J.E.B. v. Alabama, 511 U.S. 127 (1994), a party cannot remove a juror solely for the juror’s race or gender.

Guarantee of a Fair Trial

The Fifth Amendment's guarantee of due process requires that criminal defendants receive a fair trial. In high-publicity trials, trial judges have the responsibility to minimize effects of the publicity on jurors’ decisions, such as through implementing a gag-order on the parties. In Carey v. Musladin, 549 U.S. 70 (2006), the Supreme Court held that a jury was not unduly influenced by the family of the victim wearing buttons with the picture of the victim on them. 

Other Miscellaneous Guarantees

Due process further commands that defendants have the right to call their own witnesses, mount their own evidence, and present their own theories of the facts. The prosecution must turn over all evidence that will be presented against the defendant and allow the defendant pre-trial access to question the prosecutor's witnesses to properly mount a defense.

Pre-trial would also be the point at which the defense might raise a defense of double jeopardy, if such a defense existed in that case. The Fifth Amendment, through the Double Jeopardy Clause, prohibits states from charging the same defendant with substantially the same crime on the same facts.

Trial Procedure

Once a trial begins, the U.S. Constitution affords further rights to criminal defendants. The law only permits the prosecution to overcome the defendant's presumption of innocence if they can show the defendant's guilt beyond a reasonable doubt. This very high burden differs drastically from a civil trial's much lower standard in which the plaintiff must only prove a claim by a preponderance of the evidence.

One right guaranteed by the Sixth Amendment is the right of an individual to confront witnesses. The difficulty of upholding this right arises when a witness testifies to the police and passes away shortly after. In such a case, the prosecution would be unable to allow the defendant to cross-examine the witness. 

Right to Effective Counsel

The Sixth Amendment also guarantees a defendant the right to assistance of counsel during trial. If a defendant cannot afford an attorney, the government is required to provide one. Such defendants receive legal representation from the Public Defender's Office. The Federal Rules of Criminal Procedure provide that an accused shall have access to counsel at every stage of the proceedings, beginning with the defendant's initial appearance. If a defendant demands the presence of counsel during police interrogation, police must stop the interrogation until the defendant's counsel is present. In Gideon v. Wainwright, 372 U.S. 335 (1963), the Supreme Court held that the Sixth Amendment's guarantee of counsel applies to state criminal proceedings as well.

However, a defendant may choose to voluntarily and intelligently waive assistance of counsel and self-represent. This is called "pro se" representation.

The legal counseling received must also constitute "effective counseling." Ineffective assistance of counsel may serve as grounds for a new trial. Establishing ineffective assistance of counsel requires establishing that the prevailing professional norms at the time of trial render the actual assistance received inadequate and that the ineffective assistance caused a fundamentally unfair result.

Right not to Self-Incriminate

Under the Fifth Amendment of the U.S. Constitution provides that a defendant enjoys a right of not having to provide self-incriminating testimony. At the stage of a trial when the jury determines guilt or innocence, a jury cannot infer the defendant's failure to appear or answer as an admission of guilt.

Stages of a Trial


After law enforcement arrests a suspect, a judge will set the suspect's initial bail, which is a specified amount of cash that allows the defendant to get out of jail after the initial arrest. If the defendant shows up for the proper court dates, the court refunds the bail, but if the defendant skips the date, then the court keeps the bail and issues a warrant for the individual's arrest.


The arraignment comes next. During an arraignment, a judge calls an individual charged with committing a crime, reads to the individual the criminal charges against laid against them, asks the accused whether the accused has access to an attorney or needs the assistance of a court-appointed attorney, asks the accused to plead, decides whether to amend the initial bail amount, and sets the dates of future proceedings.

Preliminary Hearing

The preliminary hearing follows the arraignment. At the preliminary hearing, the judge determines whether enough evidence exists for the prosecution to meet its burden of persuasion. The burden of persuasion refers to whether the prosecution even has enough evidence to make the defendant stand trial. The defense has the right to cross examine the government witnesses during this proceeding. Under the Fifth Amendment, a grand jury, rather than a judge, makes this determination when the defendant is charged with a "capital or infamous crime.” 

Pre-Trial Hearing

A pre-trial hearing is the next step in the process. The prosecution and the defense team use the pre-trial to file motions before a judge. These motion usually concern whether the court should suppress certain evidence, whether certain individuals can testify, or whether the judge should dismiss all charges for lack of evidence.


After all these preliminary stages, the defendant stands trial. Both sides offer opening statements first, although the defense can reserve their opening statement until the prosecution “rests”—finishes presenting their case. The prosecution presents its witnesses and evidence first. Then, the defense presents its witnesses and evidence. After the defense rests, the defense offers a closing argument, and then the prosecution offers its final closing argument. After closing arguments, the jury deliberates and returns a verdict.



Sentencing usually occurs immediately for infractions and misdemeanors. For such minor infractions penalties may include probation; fines; short-term incarceration; long-term incarceration; suspended sentence, which only takes effect if the convict fails to meet certain conditions; payment of restitution to the victim; community service; or drug and alcohol rehabilitation.

More serious crimes result in the trier of fact hearing evidence and arguments from both the prosecution and the defense regarding the appropriate sentence. Some jurisdictions allow the judge alone to determine the sentence; others will have a separate sentencing phase trial, complete with a new jury, to determine the sentence for certain crimes.

During a sentencing trial, the prosecution presents evidence of aggravating factors, and the defense presents evidence of mitigating factors. The U.S. Supreme Court has interpreted the U.S. Constitution to protect the right to a jury sentencing trial for all defendants facing the death penalty.


Before the judge announces the sentence, a defendant is entitled to allocution. Allocution is the right of the defendant to directly address the judge without the help of counsel. During this direct address, the defendant may offer a personal explanation of any unknown facts, may ask for mercy, or may offer an apology for the criminal behavior. This is an opportunity for defendants to show remorse or to offer the motivations behind their criminal acts, to influence the judge to be lenient.

Sentencing Guidelines

The federal government and state governments have created various sentencing guidelines. Federal courts use the Federal Sentencing Guidelines, while state courts will look at state-specific sentencing guidelines.  

Further Reading

For more on criminal procedure, see this Columbia Law Review article titled Criminal Procedure and the Good Citizen, and this University of Nevada Law Journal Forum article titled Statewide Rules of Criminal Procedure: A 50 State Review.

[Last updated in July of 2022 by the Wex Definitions Team]