In his first year in office, Donald Trump and his administration have launched a daunting number of direct and open attacks on long-respected American rights and freedoms—threatening immigrants, the media, health care, transgender rights in the military, and much else. But there have been other, indirect and behind-the-scenes attacks, too, which may be no less damaging to the United States in the long term.

Perhaps the most critical of these is aimed at the census. Under Article I, Section 2 of the Constitution, “the whole number of persons in each State” must be counted “every … ten years.” Based on these decennial census results, the government decides, among other things, what to spend on schools, where to direct funding for health care and infrastructure, and how to allocate our representatives in Congress and in state legislatures. But under the Trump administration, the census, which has serious implications for the rights and daily lives of all Americans, seems likely to prove to be both unfair and inaccurate, and its consequences will remain in place for at least the next ten years—until the next census.

The history of the census is controversial. As originally drafted, the constitutional provision calling for the decennial census followed the three-fifths clause, which stated that the count of citizens would include, in addition to “free Persons,” “three-fifths of all other Persons.” In other words, the census, as initially embedded in our founding document, was based on the dehumanization of enslaved people. Moreover, census results have in certain instances been improperly used. Most notoriously, during World War II the War Department used existing census records to compile a database of citizens and foreign nationals thought to be dangerous. This enabled the internment of Japanese-Americans after the attack on Pearl Harbor.

In the latter half of the twentieth century, the United States took significant steps to address these problems. In 1978, Congress passed legislation establishing the “72-Year Rule,” which prohibits the release of personally identifiable information about an individual until 72 years after it was collected for the decennial census. This rule and other privacy protections surrounding the census have been vigorously enforced: In 1980, for example, FBI agents went to a Census Bureau office in Colorado Springs with warrants authorizing them to seize documents there. They were turned away by a census employee, and the dispute escalated to include both the Census Bureau director and the director of the FBI. It ended with an agreement that only sworn census employees would review census documents, but that they would provide a report for the FBI—excluding all confidential information. And in 2000, Census Director Kenneth Prewitt apologized for the role that the census played in the internment of Japanese-Americans.

The census has also undergone changes in its design to achieve more accurate counts. Between 1970 and 2000, the Census Bureau used two questionnaires. Most households received a short-form version, which asked a limited number of questions. A smaller percentage of households also received a long-form questionnaire with additional questions, as part of an effort to assist with federal planning. Undercounting of demographic groups was a glaring issue: In 1970, for example, more than 6 percent of African Americans went uncounted, compared to 2 percent of whites.