What is the police–informant privilege? What is its rationale, and what are some exceptions to this privilege?

Question

What will be an ideal response?

Answer 1

To encourage people to provide information, governments must be able to assure those people that their identity will not be disclosed, whether it is a private citizen voluntarily providing the information or a person providing information for money or other consideration. Common law has always recognized the informant's privilege as an essential aid to law enforcement. Today, many states have enacted statutes defining the privilege, while other states and the federal government use the privilege in its common-law form. The Supreme Court held that the limits of the privilege arise from fundamental requirements of fairness.
Where the disclosure of an informer's identity, or of the contents of his communication, is relevant and helpful to the defense of the accused, or is essential to the fair determination of a cause, the privilege must give way. In these situations the trial court may require disclosure. It is unlikely that a court will order the disclosure of the identity of an informant unless the informant was present at the scene of the crime charged, participated in the crime charged, or was at the scene of the arrest. If the court orders the identity of an informant, two options are available: either drop the criminal charge against the defendant, which means that the defense has won its case because this is what the defense lawyer seeks, or disclose the identity of the informant if this is practical and go to trial, possibly using the informant as a witness.