Last August, the National Academies of Sciences, Engineering, and Medicine issued a report on the U.S. Department of Commerce’s decision to add a citizenship question to the 2020 census. Prepared by some of the nation’s leading statisticians, including two former U.S. Census Bureau directors, the report concluded that the decision was “inconsistent with” what the Bureau is supposed to be doing. This conclusion rested on three points, two of which were already circulating in public conversations: Citizenship data is available elsewhere, and there isn’t enough time to test the new question, which means results could prove to be untrustworthy, making for bad science.

The third point, however, has received scant attention: The committee concluded, upon examining documents tied to the proposal, that without saying as much, Commerce Secretary Wilbur Ross was asking the Census Bureau to help create a national population registry. Robert Groves, chairman of the National Academies committee that produced the report and a former Census Bureau director, called this “a bright line being crossed.”

While the census has long collected data from household residents — including name, age, sex, and race — by law such information must remain confidential, and it cannot be shared with law enforcement or used for the purposes of identifying any one individual. But according to an analysis of questions planned for the forthcoming 2020 census, and produced by the Census Bureau last March, answers to a citizenship question could be used to supplement data from other agencies to create a “comprehensive statistical reference list of current U.S. citizens.” And it’s precisely that sort of phrasing that has given everyone from statisticians to privacy and civil rights advocates pause. The only reason to have a registry of this kind, said Groves, is “you do something with people who are on the registry, and [who are] not on the registry.”

A New York lawsuit, one of seven filed in opposition to adding the question, has already produced a judge’s ruling against Ross’ plans. The federal government has appealed that decision and petitioned the Supreme Court to hear the case. Department of Commerce spokesman Kevin Manning, meanwhile, declined to comment on this story due to pending litigation, and he would not say if Ross had even read the National Academies report.

Love Undark? Sign up for our newsletter! Email *

Still, while the Census Bureau analysis describes the 2020 citizenship question as a one-time query, a March 2018 memo from Ross makes no mention of this temporary status. The memo asserts that the Department of Justice requested the citizenship question in December 2017, in order to uphold the Voting Rights Act. But documents released through legal discovery reveal that the Kansas Secretary of State at the time, Republican Kris Kobach, spoke with Ross in the spring of that year about adding the question. He did so, the documents suggest, at the direction of Steve Bannon, the former adviser to President Donald J. Trump and prominent right-wing figure in American politics.

Whatever Ross’ intent, using the census to build a population registry is both legally questionable and socially dangerous, critics say. These critics include Margo Anderson, an emeritus professor of history and urban studies at the University of Wisconsin, Milwaukee and an expert on the history of the American census. Anderson and her colleague, Fordham statistician William Seltzer, worked for decades documenting how population registries were used, for example, to target Australian Aborigines in the late 19th and early 20th centuries; Jews in the Netherlands and Norway during World War II; and Tutsis in the Rwandan genocide of 1994, among other cases.

Most importantly, Anderson reiterated, the U.S. Census, by law, cannot be used to identify individuals — and it is designed expressly to prevent statistical data regarding individuals from being “turned into law enforcement or some other targeting.”

The citizenship question on its face has raised concerns among immigrant rights advocates, although this is not the first time that citizenship status has appeared on the U.S. census form. Indeed, it appeared every decade from 1890 until 1950, in one form or another. But it’s less the question itself and more the possible plans for the data that have most raised legal eyebrows — and concerns about “registries.”

The difference between a census and a registry is nuanced, but those nuances matter. A census uses aggregated individual responses to survey questions asked of an entire population at a particular point in time. That produces statistical information to be used for everything from drawing congressional districts to funding government programs. A registry, on the other hand, is a continually-updated database that allows a government to identify where every individual lives at any time and to track different characteristics of those individuals.

In preparing its report, the National Academies committee reviewed Secretary Ross’ memo, which names four options for getting a more accurate idea of the nation’s population of citizens and opted for the fourth, “Option D.” According to the Census Bureau’s March 2018 analysis, this option essentially rested on adding the citizenship question to the 2020 census and cross-referencing answers to that question with data from a series of administrative agencies, including the U.S. Citizenship and Immigration Services department and the Internal Revenue Service, in order to develop a comprehensive database of citizens and non-citizens.

It was in that Census Bureau analysis — in what Groves called “only a few words” — that the National Academies group found the notion that most alarmed them. “There would be no plan to include a citizenship question on future Decennial Censuses or American Community Surveys,” the study declared. “The comprehensive statistical reference list, built from administrative records and augmented by the 2020 Census answers would be used instead. The comprehensive statistical reference list would be kept current, gradually replacing almost all respondent-provided data with verified citizenship status data.”

In other words, the National Academies committee wrote in its report, Secretary Ross was seeking to use “census responses as seed data to construct an ongoing citizenship status registry.”

The group’s members asked each other, “Why does the country need a registry of citizens?” Groves recalled.

Secretary Ross has yet to answer that question, or to address the issue in public — and in the absence of clearly-demonstrated motives for seeking more data on citizenship, it is not entirely apparent that he truly intends to create a population registry. Still, historians and social science researchers are quick to point to what Ellen Percy Kraly, a geography and environmental studies professor at Colgate University, calls the “dark underbelly” of population data. Kraly has studied, for example, how local Australian government officials used population registries to control Aborigines, as in the case of A.O. Neville, who held the position of Chief Protector of the Aborigines in Western Australia in the early 20th century and was the subject of the movie “Rabbit Proof Fence.”

Neville maintained “index cards for every single [Aboriginal] person” in Western Australia, Percy Kraly says — about 5,000. He kept information about their names, land, race, and more. One way he used the data was to identify lighter-skinned Aboriginal children and remove them from their families, to marry them into families of European descent. The idea was to use individual, current information on all the native people in Western Australia to gradually eliminate them through eugenics.

Of course, registries are used in countries like Sweden, Italy, and Poland to serve as the basis for national programs, such as universal health care. “If you have a national health care system, it’s more obvious you get a benefit” from having your personal information used in a registry, said Jerry Reiter, a professor of statistical science at Duke University who also holds a part-time position at the Census Bureau, where he works on protecting data confidentiality.

Department of Commerce Secretary Wilbur Ross has expressed interest in a “comprehensive statistical reference list of current U.S. citizens.” Critics are crying foul. Visual: Sylvain Gaboury/Patrick McMullan via Getty Images

If the National Academies committee is right, and Ross is seeking to develop a population registry for the United States, it wouldn’t be the first time the idea has surfaced in connection with keeping track of who is and isn’t a citizen.

Recently, Anderson submitted expert testimony for federal litigation filed in San Francisco against the citizenship question, one of a handful of lawsuits nationwide. In her testimony, she recounts a little-remembered moment in the months before the 1980 census, which “would report over 14 million foreign-born residents, roughly a 40 percent increase compared to the 1950 -1970 period,” she wrote.

The marked increase in foreign-born residents caused political concern for months leading up to the 1980 census. Anti-immigrant groups lobbied Congress to do something about this growing population. In response, Senator Walter D. Huddleston (D-KY) introduced legislation to require the Census Bureau to produce more comprehensive estimates of the undocumented immigrant population; he said he was concerned that “distortions” in total population counts could affect redistricting and other efforts.

Then-Census Bureau Director Vincent Barabba testified before the Senate, expressing concerns about the lack of time the Bureau would have to enact the new program. He further stated, “There is some concern in my mind, whether our reputation of being able to keep information confidential, would in any way be tarnished in this kind of a program,” which might be perceived as serving law enforcement. As Anderson outlines in her report, Barabba cautioned against “entangling the census in immigration policy.”

The Census Bureau director raised one final point: “There would be a tremendous concern on my part,” he said, “that we would have to install a procedure which I am not sure society is ready for, as they do in other countries — registration lists, or even closing society down and holding everybody in place.” The bill never moved through Congress, and the parallels between these events and today are striking.

“These are 30- to 40-year-old questions,” Anderson said in an interview with Undark, after describing Barabba’s testimony. “They’ve been resolved. The U.S. statistical system is not designed to initiate or maintain a national population registry.” Further, Americans have a history of rejecting proposals if they even have the comprehensive, sweeping feel of a registry. Steven Ruggles, professor of history and population studies at the University of Minnesota, recalls that “in the 1960s, my dad’s proposal for a national data bank was shot down” in Congress.

As Anderson described in her book, “The American Census: A Social History,” in 1965, Yale economist Richard Ruggles proposed a “federal data center, with public access for researchers” that would centralize and coordinate data from disparate sources. But the idea drew “almost immediate consternation from members of Congress,” as it became tangled in a “messy and diffuse discussion about ‘privacy’ and intrusive state surveillance,” Anderson writes.

Members of Congress were “making noise about Big Brother,” Steven Ruggles said. The proposal was never realized. Reaction to it was evidence of what Ruggles called “a paranoid streak” in American culture. That streak, he said, is why a national registry will “never be politically feasible.”

“Our country is a wonderful melting pot of all sorts of ideas and backgrounds — people who trust the government, and people who don’t,” said Reiter. “That makes it more difficult and unlikely to have a population registry, with people saying, ‘I don’t want the government to have all my information.’”

At the same time, such concerns may be misplaced, at least when it comes to comparing the potential impacts of a census and a national registry, Ruggles said. “You can use census data to round up a group” of people, he noted. Indeed, Anderson’s research also exposed how U.S. census data was used in World War II to locate Japanese Americans living in the Washington, D.C. area, potentially for surveillance and internment.

John Thompson, who worked at the Census Bureau from 1975 to 2002, and again, as director, from 2013 to June 2017, has publicly weighed in against asking the citizenship question, but not due to concerns that motivations behind the proposal may include developing a population registry. Instead, his concerns are more immediate and practical. “Basically, my position is that the citizenship question [has] not been adequately tested,” he said. Thompson submitted expert reports for one lawsuit against adding the question filed in New York, and for another filed in Maryland. “I described what adequate testing procedures would be. Previous censuses have gone through these procedures with proposed changes.”

In his affidavit for the New York case, Thompson described how, following the 1990 census, the Bureau began four years of cognitive and field testing of a question allowing respondents to indicate that they identified with multiple races, according to the plaintiffs’ filing. More than a decade of additional testing on race and ethnicity questions began in 2008, including a questionnaire sent by mail, follow-up telephone interviews of respondents, and a series of focus groups.

No such testing has been done on the proposed citizenship question, Thompson noted. In order to do this, the Census Bureau must have “a clear understanding of the desired uses of the new data so that the new question can be worded to achieve the desired outcome,” according to the filing.

But since the supposed reason for the question — to shore up voting rights — proved false, and an actual reason has not been clearly established, “One can only speculate about the motives” behind Secretary Ross’ plans, Thompson said. This absence of clarity led Thompson to highlight something about countries with population registries: “A population registry, in countries that have one, is shared with everyone — and it’s openly stated by the government what the purpose is.”

Continuing with the 2020 census as planned “would be like creating a population registry without asking everyone if it was okay,” said Don Dillman, a member of the National Academies committee, deputy director for research and development in the Social and Economic Sciences Research Center at Washington State University, and a founder of one of the first university-based telephone survey research centers. The impact of doing so “worries me a lot,” he added.

As the committee reviewed many of the materials that recent lawsuits have turned up, Dillman “really started wondering if the citizen question was put there to identify people.” Not knowing what would be done with information gathered from answers to the question and administrative sources, as well as being unsure about the real motivation behind adding the question, also made him anxious about the scope of its impact. “If it’s really a registry,” Dillman said, “I don’t know where it would start — and where it would end.”

Groves says he feels so strongly about the issue that if he were Census Bureau director, he would say, “‘If you insist on doing this — building a registry — I would have to resign.’” He went on to say that he doubted Census Bureau rank and file would stand for it. “The code of ethics is so deeply held that people would be calling from the bowels of the Census Bureau saying, ‘Do something about this.’”

Timothy Pratt is based outside Atlanta. He has worked with The New York Times, The Guardian, The Associated Press, Reuters, and many other outlets, covering race, immigration, science, soccer, and more, in English and Spanish.