The Founders believed that “a man’s house is his castle,” and should be free from the arbitrary government intrusion that frequently occurred under kings and queens. Not all private activity during the 19th century, however, was free from government intrusion. Although privacy of the mails was protected, many states prohibited interracial marriage.

A rapidly industrializing world transformed ideas about privacy. As more Americans left their families to work in cities, they enjoyed greater sexual freedom. However, new technologies, such as the telephone and camera, expanded surveillance techniques. Several Federal agencies increasingly used state power to investigate suspected criminals and to discourage “deviant” sexual activity.

World War II and Cold War anxieties altered the boundaries of privacy rights. In 1940, President Franklin Roosevelt issued a secret directive authorizing the FBI to wiretap persons suspected of “subversive activities.” Counterintelligence efforts intensified in the name of national security. Federal agencies sought to eradicate groups they believed were security threats, including homosexuals.

As the century progressed, more Americans called for a constitutional right to privacy. The U.S. Supreme Court handed down several landmark decisions that created a “zone of privacy” under the Constitution, and firmly established the concept of privacy in American law. However, as the Right to Life movement and disputes over the PATRIOT Act reveal, privacy remains a contested right.