By Professors Jeffrey Fagan and Bernard E. Harcourt
Columbia Law School
What is a grand jury and what does it usually do?
Grand jury practice is determined on a state-by-state basis. The U.S. Constitutional right to a grand jury indictment in a felony case, included in the Fifth Amendment,
 has not been
incorporated as to the states and thus does not apply to state prosecutions. Many state constitutions require a grand jury indictment in certain cases and specify the powers of a grand
jury. The practices of grand juries thus vary by state and federal jurisdictions.
About half the states require a grand jury indictment for prosecution in felony cases. In those states that do not require a grand jury indictment, cases will generally proceed on the basis
of an information filed by the prosecutor. This becomes the charging instrument. As a general matter, prosecutors will try to avoid presenting a case to a grand jury when possible in
order to avoid creating testimony that can be used to cross-examine a witness at trial, unless the prosecutor is trying to use the grand jury as a way to develop evidence for a
prosecution. In controversial cases, state law will often allow the appointment of a special or independent prosecutor.
Grand juries are standing juries, drawn from the regular jury pool, ready to hear evidence presented by prosecutors.
Rules and procedures vary by jurisdiction.
Their size ranges from
23 (federal) to 12 (Missouri).
Grand juries do not always need to be unanimous.
In Missouri, for instance, 9 of 12 grand jurors can return an indictment. Grand juries will often sit for
weeks at a time and may hear dozens of potential cases.
Grand jury proceedings are closed to the public and to the media, as well as to the targets of the investigation and their counsel. Generally, the only persons in the grand jury room are
the jurors, the prosecutors, and the witness who is called. Most often, the practice is for the prosecutor to preside over the process without a judge in the grand jury room. The
prosecutor typically instructs the jury on the law.
Generally, grand juries will issue indictments in most if not all cases. The standard for indictment is probable cause.
In the context of the grand jury, the Supreme Court has stated,
“Probable cause, we have often told litigants, is not a high bar: It requires only the ‘kind of “fair probability” on which ‘reasonable and prudent [people,] not legal technicians, act.’”
The grand jury process is now so routinized in most state jurisdictions that it has become a
proceeding to deliver an indictment for a prosecutor. It is for this reason that most
lawyers say, repeating the famous expression of the former chief judge of the highest New York state court, Sol Wachtler, that prosecutors can get grand juries to “indict a ham
 According to the Bureau of Justice Statistics, “U.S. attorneys prosecuted 162,000 federal cases in 2010, the most recent year for which we have data. Grand juries