In March of 2018, the Trump administration announced the addition of a citizenship question to United States Census. Last week the Supreme Court put a hold on their plans, sending the case back to a lower court and telling the government to focus their argument. The administration acquiesced, saying the question would not be included. Then the president sent out a tweet.
The history of the Census, its use and misuse, and the controversy over if and why a citizenship question should be included; this week on Context, Please.
In August of 1943, the Secretary of the Treasury sent a request to the Secretary of Commerce, requesting complete, unredacted Census data on every Japanese-American living within the D.C. metro area in order to protect the President. This request was granted. Such a use of data goes explicitly against the Census' clear mandate to be confidential.
Similar procedures likely contributed to the federal government's ability to quickly detain and incarcerate mass numbers of Japanese-Americans, though complete documentation has not been uncovered.