A shield law is legislation designed to protect reporters' privilege. This privilege involves the right of news reporters to refuse to testify as to information and/or sources of information obtained during the news gathering and dissemination process. Currently the U.S. federal government has not enacted any national shield laws, but most of the 50 states do have shield laws or other protections for reporters in place.
A shield law is law that gives reporters protection against being forced to disclose confidential information or sources in state court. There is no federal shield law and state shield laws vary in scope. In general, however, a shield law aims to provide the classic protection of, "a reporter cannot be forced to reveal his or her source" law. Thus, a shield law provides a privilege to a reporter pursuant to which the reporter cannot be forced by subpoena or other court order to testify about information contained in a news story and/or the source of that information. Several shield laws additionally provide protection for the reporter even if the source or information is revealed during the dissemination of the news story, that is whether or not the source or information is confidential. Shield laws do not ensure absolute protection. Depending on the jurisdiction, the privilege may be total or qualified, and it may also apply to other persons involved in the news-gathering and dissemination process as well, such as an editor or a publisher.
The issue of whether or not journalists can be subpoenaed and forced to reveal confidential information arose in 1972 with the United States Supreme Court case Branzburg v. Hayes. Paul Branzburg was a reporter for The Courier-Journal in Louisville, Kentucky and wrote an article about the drug hashish. In creating the article, he came in contact with two local citizens who had created and used the drug. Because their activity was illegal, Branzburg promised the two individuals that he would not reveal their identities. After the article was published, Branzburg was subpoenaed by a local grand jury and ordered to reveal the identity of his sources. Branzburg refused and cited the provisions for freedom of the press from the First Amendment of the Constitution, in his defense.
The case eventually reached the U.S. Supreme Court, where the court decided in a five to four decision that the press did not have a Constitutional right of protection from revealing confidential information in court. The court acknowledged, however, that the government must "convincingly show a substantial relation between the information sought and a subject of overriding and compelling state interest." While this ruling did not set a precedent for journalistic rights in court, it did define a more stringent set of requirements for when a journalist could be subpoenaed in court.