David T. Z. Mindich, a professor of media studies, journalism and digital arts at Saint Michael’s College, is the author of “Tuned Out: Why Americans Under 40 Don’t Follow the News.”

COLCHESTER, Vt. — BY leaking details of the National Security Agency’s data-mining program, Edward J. Snowden revealed that the government’s surveillance efforts were far more extensive than previously understood. Many commentators have deemed the government’s activities alarming and unprecedented. The N.S.A.’s program is indeed alarming — but not, from a historical perspective, unprecedented. And history suggests that we should worry less about the surveillance itself and more about when the war in whose name the surveillance is being conducted will end.

In 1862, after President Abraham Lincoln appointed him secretary of war, Edwin M. Stanton penned a letter to the president requesting sweeping powers, which would include total control of the telegraph lines. By rerouting those lines through his office, Stanton would keep tabs on vast amounts of communication, journalistic, governmental and personal. On the back of Stanton’s letter Lincoln scribbled his approval: “The Secretary of War has my authority to exercise his discretion in the matter within mentioned.”...