In a legal sense, when someone is granted immunity, this means that he has been granted an exemption from a legal requirement or consequence. Examples of immunity include releases from payments or penalties. Immunity from prosecution is a legal doctrine that permits a person to avoid being prosecuted for a criminal offense. This is usually granted in exchange for something that the prosecution needs, such as information about someone else who has committed a more serious crime. To explore this concept, consider the following immunity definition.

Definition of Immunity


  1. Exemption from criminal prosecution, legal liability, punishment, or other consequence on certain conditions.


1350-1400       Middle English immunite

What is Immunity

Immunity is often used as a tool by the prosecution to get someone who has committed a minor crime to testify against someone who is charged with a more serious offense. In exchange for the testimony of the person who committed the minor crime, the prosecution will agree to drop the charges against that person, thereby granting him immunity. As an example, immunity might be granted by a prosecutor to a small-time drug dealer, in exchange for his testimony against a more powerful drug lord.

Immunity can be granted to witnesses involved in crimes of varying degrees of seriousness, from the selling of drugs, to kidnapping and murder. However, immunity is not always a no-strings-attached kind of deal. The prosecution can still choose to renege on the deal and pursue the witness in the future.

Backing Out on an Immunity Deal

If the prosecution does decide to seek an indictment against a witness who has been immunized, then they must be able to show that the case they are pursuing has nothing to do with the immunized testimony that was given by that witness. Someone who is granted immunity but then refuses to testify, on the other hand, can be held in contempt of court. An individual backing out on an immunity deal may also be subjected to fines and imprisonment, in addition to the consequences of the original crime, as he has nullified the deal.

Similarly, the immunized witness who is prosecuted anyway, and intends to claim immunity from the prosecution, must be able to show that the prosecution granted immunity. He must also be able to show that the testimony in question is related to the charges at hand. Once he does that, then the burden of proof shifts to the government.

The prosecution must then show that all the evidence they intend to use comes from independent sources. If the prosecution was privy to immunized testimony, then they must show, with either written or oral statements, how they found evidence against the witness that was independent of that testimony. If a judge determines that the prosecution is improperly using immunized testimony, then the prosecution will be prohibited from using that testimony at trial. If there is no evidence present that was gained independently of the immunized testimony, then the court will dismiss the case outright.

Waiving Immunity

An immunized person can choose to waive his immunity. One way of doing this is to simply state, for the record, that he intends to waive his immunity. One of the reasons for waiving immunity is because he did not claim immunity in time. For instance, if a witness gives an incriminating statement and does not reveal that he has immunity until the trial has already begun, then it may be too late for him to benefit from the immunity he had previously been granted.

Immunity can also be waived even before a witness receives it. This happens when a witness testifies voluntarily without being protected by immunity. Once a person has waived his immunity, then the testimony he gave is no longer immunized, and the government is free to prosecute him based on the material within his testimony.

Types of Legal Immunity

Typically, there are four types of legal immunity. These include:

  • Immunity from Criminal Prosecution – This is a promise that a person will not be prosecuted for a specific crime, in exchange for his testimony or information he may have in a criminal matter. It can be granted by a judge, a grand jury, or the prosecution.
  • Protection for Public Officials – Immunity here works to protect public officials from liabilities they might incur from the decisions they make.
  • Governmental Immunity – This type of legal immunity works to protect government agencies from lawsuits, unless the government agrees to the lawsuit.
  • Diplomatic Immunity – This type of legal immunity provides exemptions for foreign ambassadors from most of the United States’ criminal laws.

Diplomatic Immunity

Diplomatic immunity is an example of immunity that protects diplomats from being prosecuted under U.S. law. However, diplomats who are protected by diplomatic immunity can still be expelled from the country. The concept of diplomatic immunity emerged as a way for the country to grant certain privileges and immunities to diplomats to ensure that they can still effectively carry out their responsibilities on foreign soil. For instance, a diplomat who is accused of spying may be granted immunity if it is determined that the act was ultimately beneficial to the country’s safety.

It is expected that, if the U.S. grants these privileges to visiting diplomats, U.S. officials would be granted the same courtesy if they were to visit that diplomat’s country in the future. Further, like an individual witness, it is possible for a diplomat’s home country to waive immunity. However, this usually only happens when the diplomat has committed or witnessed a serious crime that is not related to his diplomatic role.

Many countries refuse to waive immunity, though, and may choose to prosecute the diplomat themselves. Diplomats themselves are typically not authorized to waive their own immunity. If a diplomat’s immunity is waived, this means that the government intends to prosecute him. This is done when it is decided that it is in the public’s best interests to prosecute the diplomat. Such an instance would be if a diplomat was being accused of murder. His immunity might then be waived so that he could be tried for the crime.

Immunity Example Involving Unlawful Detainment

Lavoni Kidd was born in Wichita, Kansas, and was a stellar football player at the University of Idaho. While in college, Kidd decided to convert to Islam and, in doing so, changed his name to Abdullah al-Kidd. In 2003, al-Kidd was arrested by federal agents at the Dulles International Airport, where he was headed to Saudi Arabia to study Arabic and Islamic law. He was held for over two weeks as a material witness in the terrorism trial of Sami Omar al-Hussayen, who was being tried for supporting terrorist organizations and was ultimately acquitted.

At the time of al-Kidd’s arrest, the director of the FBI told Congress that the arrest was one of the FBI’s “success stories” in the fight against terrorism. Al-Kidd was never charged with a crime, never called as a witness, and was ultimately released. Al-Kidd sued John Ashcroft – the former Attorney General – personally, alleging that Ashcroft created a program that misused the material witness statute to detain those who were suspected of being terrorists.

Additionally, al-Kidd claimed that he was denied the opportunity to call his lawyer, and that he was also shackled and strip-searched. The American Civil Liberties Union (ACLU) stepped in to represent al-Kidd, and claimed that he was one of 70 Muslim men who found themselves in similar situations.

The federal government argued that Ashcroft had absolute immunity from civil suits of this nature because he was acting within the scope of his responsibilities as the Attorney General. Further, Ashcroft enjoyed qualified immunity, which prevented suits like this from going forward unless an official violated a right that was made clear at the time the violation occurred.

The lawsuit never went to trial, and in September 2009, the Court of Appeals for the Ninth Circuit rejected Ashcroft’s request for absolute immunity. The Court held that Ashcroft could indeed be sued personally, and be held responsible for the wrongful detention of al-Kidd. This was because the government’s objective in arresting al-Kidd was allegedly entirely unrelated to the al-Hussayen prosecution. In October of 2010, the U.S. Supreme Court agreed to hear Ashcroft’s appeal of the Court of Appeals’ decision.

In a unanimous ruling, in May of 2011, the Supreme Court reversed the lower court, ruling that al-Kidd’s attorneys had not met the burden of proof necessary to show that Ashcroft could be sued in his personal capacity. Further, al-Kidd’s attorneys had failed to show that Ashcroft was directly involved in, and/or possessed detailed knowledge of, al-Kidd’s detainment. This suggested that the matter was handled mainly by Ashcroft’s subordinates, not Ashcroft himself.

That being said, the injustice committed against al-Kidd did not go unrecognized by the Court. Supreme Court Justice Ruth Bader Ginsburg addressed the Material Witness Statute, writing that:

“[This] ordeal is a grim reminder of the need to install safeguards against disrespect for human dignity, constraints that will control officialdom even in perilous times.”

The Material Witness Statute pertains to those who may have information concerning a criminal proceeding. However, after the terror attacks that occurred on September 11, 2001, the statute has been employed to detain suspects for indefinite periods of time, and without officially charging them with a crime. Due to the controversy surrounding the statute, the details of the statute warranted judicial review.

Related Legal Terms and Issues

  • Burden of Proof – The obligation to prove one’s claim.
  • Contempt of Court – A willful act of disobedience to an order of the court; deliberately being rude or disrespectful to the judge or the court.
  • Detainment – To keep (a person) in custody.
  • Civil Lawsuit – A lawsuit brought about in court when one person claims to have suffered a loss due to the actions of another person.