Letters to and from soldiers became the subjects of deliberate censorship first starting in the Civil War.¹ From there, the practice became more and more commonplace, especially during both World Wars. Oftentimes, heavy censoring was done in prisoner-of-war camps, where the individuals sending the letters were not trusted. In later wars, however, it became commonplace for letters by soldiers from the United States to be checked as well. Censors would look for any information divulging specific locations or war plans.
In the case of prisoners who did not speak English, their letters would either be vetted by a censor who did speak the language, or they would not be sent at all. All correspondences had to be sent in English if the censor who spoke the foreign language was absent.²
The actual censoring was typically done by an officer within the army or by someone in the Federal Bureau of Investigation (FBI). To avoid being censored, the person writing the letter would specify that they “can’t say much or the censors will cut it out” ¹. Drawing attention to the presence of it was the easiest way to avoid a letter being censored, since context is provided to accommodate for the lack of information.