Nowadays, carrying a passport goes hand-in-hand with traveling abroad. But it wasn’t always that way. Craig Robertson, an assistant professor of communication studies at Northeastern University, explores how the modern passport came to be in his new book, The Passport in America: The History of a Document. Robertson highlights the passport’s emergence as an identification document — in essence, how a piece of paper came to be accepted as a reliable and accurate answer to the question, “Who are you?”

How did the modern passport take shape?
Early passports issued by the State Department worked more as letters of introduction. Initially, there wasn’t even a description of the person. For people who could afford to travel, a passport represented a status symbol, but they weren’t required in order to cross American borders.
The passport ultimately changed to an identification document, and World War I was the catalyst. During the war, most countries introduced emergency passport requirements that became permanent in the 1920s under the guidance of the League of Nations. As a large population started to travel again, people encountered this demand for an identification document.

How did the public react?
It was the first time people of a well-off class encountered a demand to prove their identities. There was shock that their identities were reduced to things like name, height and weight, and, before the photograph, people had to describe what their faces looked like. The romantic sense of oneself—the character and personality—just doesn’t translate to the basic format of a passport.
As a result, there was a movement in the 1920s labeled “the passport nuisance.” People were concerned about the demand to prove their identity through documents. The perception was that identification documents were for criminals and the insane, people who could not be trusted — not well-to-do folk. The application requirements were also seen as an invasion of privacy.

Today passports are often used as proof of citizenship. Was that always the case?
Until 1856, there was no actual law stating that passports had to be issued to citizens. In the midst of this uncertainty, free African Americans applied for passports as part of their demand for citizenship. After 1856, the State Department occasionally used passports to define “good citizenship.” In the late 1880s, Mormons were not issued passports on the assumption they were traveling to recruit polygamists. Until the 1920s, married couples traveling abroad were issued joint passports in the name of the husband. In the 1950s, suspected communist sympathizers were not issued passports.

Your book covers the passport’s history into the 1940s. But in a post-9/11 world, how do you think the role of the passport has changed or will evolve?
Post-9/11, foreigners are digitally fingerprinted when they enter the country. Unlike additional passport requirements, this was met with resistance. People made arguments reminiscent of the 1920s, like, “I’m not a criminal.”
The passport continues to be a very important document for national security. World War I made it so, and I think the U.S. response to 9/11 has again emphasized its significance. Both were times of war. What is missing this time is the affront of being asked for an identification document itself. We’re used to that demand now.