Since colonial times, the privacy of the mail was a significant problem. Sealing letters was difficult. Benjamin Franklin, who was in charge of the colonial mails, required his employees to swear an oath not to open mail. And in 1782, Congress passed a law that mail should not be opened.

Nevertheless, significant concerns persisted about postal clerks reading people’s letters. Thomas Jefferson, Alexander Hamilton, and George Washington frequently complained about the lack of privacy in their letters, and they would sometimes write in code. As Thomas Jefferson wrote:: “[T]he infidelities of the post office and the circumstances of the times are against my writing fully and freely.”

The burgeoning use of the telegraph raised a number of privacy problems. Shortly after the telegraph’s invention in 1844, technology to tap into telegraph communications emerged. As Priscilla Regan observes:

During the Civil War, the Union and Confederate armies tapped each other's telegraph communications to ascertain battle plans and troop movements. Rival press organizations tapped each other's wire communications in order to be the first to report major news items.

After the Civil War, Congress began to seek access to telegraph messages maintained by Western Union for various investigations. This raised a considerable outcry among some members of Congress. Additionally, a New York Times editorial decried the practice as “an outrage upon the liberties of the citizen.” Another editorial in the New York Tribune complained that the seizure of telegrams “violates the commonest legal maxims as to the right to call for papers, and outrages every man’s sense of his right to the secrets of his own correspondence.” A New York Sun editorial stated that “the idea that every curious and prying legislative committee may cause to be spread before the public everything that has been sent over the wires will be hateful and repulsive to the people in general.”

These problems resulted in a growing congressional debate about whether telegrams should be accorded similar privacy protections to letters. A bill to protect the privacy of telegrams was introduced into Congress in 1880. The bill would ultimately be abandoned. But beyond congressional attempts to obtain telegraph communications, the law responded to restrict other entities from breaching the privacy of telegrams. Several courts quashed subpoenas for telegrams, analogizing them to letters. As the Missouri Supreme Court stated in quashing a grand jury subpoena for telegrams: “Such an inquisition, if tolerated, would destroy the usefulness of this most important and valuable mode of communication.” State legislatures also responded by passing laws to prohibit the disclosure of telegraph messages by telegraph company employees. More than half the states enacted laws.