From Korematsu v. United States, 323 U.S. 214 (1944), the United States Supreme Court decision upholding the internment of Japanese-Americans:
It is said that we are dealing here with the case of imprisonment of a citizen in a concentration camp solely because of his ancestry, without evidence or inquiry concerning his loyalty and good disposition towards the United States. Our task would be simple, our duty clear, were this a case involving the imprisonment of a loyal citizen in a concentration camp because of racial prejudice. Regardless of the true nature of the assembly and relocation centers-and we deem it unjustifiable to call them concentration camps with all the ugly connotations that term implies-we are dealing specifically with nothing but an exclusion order.
That says two things:
- By 1944, the historically neutral term "concentration camp" had already achieved the negative connotations it has today, most likely because of early reports out of Nazi Germany, possibly because of the Boer War or the Armenian Genocide.
- The fact that the Supreme Court refused to call them concentration camps strongly implies the government never did in oral arguments, petitions, or other public proclamations. I don't see the Court actively avoiding a phrase that both critics and proponents of internment embraced.
I think it's a pretty good bet the term was never officially used in public communications. You quote FDR, but he was speaking a) off-the-cuff and b) summarizing what other people were saying.
Within internal communications, most instances I find of the term 'concentration camp' are from opponents of the idea. The Munson Report was the first inquiry into the idea of the camps (before Pearl Harbor, even). The author was largely opposed to the idea:
We do not want to throw a lot of American citizens into a concentration camp of course, and especially as the almost unanimous verdict is that in case of war they will be quiet, very quiet.
Again, note the use of 'concentration camp' is negative. We see something similar in a letter from Attorney General Biddle to FDR:
The important thing is to secure the reabsorption of about 95,000 Japanese, of whom two-thirds are citizens and who give every indication of being loyal to the United States, into normal American life. The present practice of keeping loyal American citizens in concentration camps on the basis of race for longer than is absolutely necessary is dangerous and repugnant to the principles of our Government.
So yes, there are some internal communications that characterized the camps as "concentration camps." But as a whole, the phrase had a stigma attached to it and was avoided.
