This year the Census Bureau will begin conducting the constitutionally required census, which takes place every 10 years. Many readers will dutifully fill out the forms, informing the bureau about their household and providing researchers with data. In May, the bureau will begin visiting those who haven’t responded to the census.

But why wouldn’t someone want to contribute to social science and an accurate head count? The history of the census provides ample evidence to justify such reluctance.

The census sounds harmless enough. In a representative democracy like the United States where seats in at least part of the legislature are determined by population, it’s important to know how many people live in the country and where they live. The framers of the Constitution codified the decennial census as the mechanism for determining the number of seats each state occupies in the House of Representatives. Yet the information included in the census has been used to violate civil liberties, and it would be a mistake to assume similar abuses won’t occur again.

Governments often overreact in the wake of a crisis, and a crucial feature of such overreactions is the collection and analysis of information. During the first Red Scare, a 24-year-old J. Edgar Hoover was put in charge of the so-called “Anti Radical Division” formed by the Attorney General A. Mitchell Palmer after a string of anarchist bombings. Hoover, who previously worked at the Library of Congress, used his librarian skills in his hunt for aliens to deport. His team assembled hundreds of thousands of index cards associated with not only individuals but publications and organizations. These notecards aided Department of Justice officials, who conducted the so-called Palmer Raids in late 1919 and early 1920. The raids resulted in thousands of people being arrested without warrants, hundreds of whom were deported.

Such zeal for data collection was not isolated to the first Red Scare. Other crises have resulted in increased information gathering. And one of the best sources of information available to the government is the census.

After the Japanese navy’s air service bombed the U.S. Navy base at Pearl Harbor in December 1941, military officials reached for the census to facilitate one of the most shameful civil liberty abuses in American history: the internment of Japanese-Americans. A few months after the attack, President Franklin D. Roosevelt issued Executive Order 9066. The order authorized the secretary of war to exclude those considered national security risks from designated military areas. As result, 120,000 people of Japanese descent — the majority of whom were U.S. citizens — were moved into internment camps.

Census officials denied that the bureau had assisted Japanese internment. But in 2000 historian Margo Anderson of the University of Wisconsin and Fordham University statistician William Seltzer uncovered evidence that Census Bureau officials provided information on whereabouts of people with Japanese ancestry. In 2000, the Census Bureau director apologized, but only a few years after the apology the bureau was aiding the surveillance of another minority group.

In August 2002 and December 2003, the Census Bureau put together tabulations of Arab-Americans for Customs and Border Protection. These tabulations included information on how many Arab-Americans lived in specific ZIP codes. The creation of these tabulations was a small part of the U.S. government’s broader overreaction to the 9/11 terrorist attacks, which resulted in widespread and needless infringements on civil liberties.

We should expect that in response to the next crisis officials won’t be shy about seeking census data. This risk is more pronounced when the targets of government surveillance come from broad groups such as “Japanese-Americans” or “Arab-Americans.” The history of American surveillance reveals a list of the targets that is long and diverse. Today the administration is concerned about illegal immigrants. This misguided concern prompted the administration to seek to add a citizenship question to the 2020 census before the Supreme Court ruled against the administration.

Future administrations will have different targets. Given that anyone could one day be on the receiving end of government surveillance, it behooves us to be hesitant to volunteer intimate details about our families.

Refusing to accurately complete a census form is against the law and could result in a fine. Fortunately, the Department of Justice is hesitant to pursue census refusal cases. It’s true that the census provides researchers with valuable data, but given the history of government overreaction to crises you could forgive those who err on the side of providing less information to the Census Bureau.