Nine years ago, two Republican senators, David Vitter, of Louisiana, and Robert Bennett, of Utah, tried to introduce a measure to change the way that the federal government conducts the census. The Census Bureau tabulates the over-all population, not just that of citizens, and its results have far-reaching consequences, affecting the allocation of federal resources and the apportionment of congressional seats. The senators wanted a law requiring that respondents be asked whether they are American citizens, so that congressional districts could be redrawn. Without such a change, Vitter said, “States that have large populations of illegals would be rewarded.” Other states, like his own, he said, were being “penalized.” The subtext was that the Democrats, who tend to be prominent in areas with high concentrations of immigrants, were gaining an advantage. The measure fell short of the necessary votes, as it did when Vitter proposed it again, in 2014 and in 2016. But his efforts reflected a persistent partisan logic. Now, on the eve of the 2020 census, it has reëmerged.

On Monday, the Department of Commerce announced that it was adding a citizenship question to the 2020 census. According to the Trump Administration, this step is “necessary for the Department of Justice to protect voters.” The Justice Department had requested the change in December, on the grounds that it needed to better enforce Section 2 of the Voting Rights Act, which is designed to prevent violations of voting rights. It was an odd claim: in 2013, when the Supreme Court struck down part of the Voting Rights Act, Attorney General Jeff Sessions, then a senator from Alabama, called the decision “good news . . . for the South.” A raft of state voter-suppression laws targeting minority voters followed, including in Texas, which passed a voter-I.D. law that a federal judge later found to be racially discriminatory. During the Obama Administration, the federal government filed a lawsuit against the state, but last year Sessions decided to drop it. “The idea that this question is being added to the census to protect minority voting rights so that the lines can be redrawn in a fair way is just too absurd to be believed,” Rick Hasen, an election-law expert at the University of California, Irvine, told me.

This week’s announcement caused an immediate outcry. Six former heads of the Census Bureau wrote to Wilbur Ross, the Commerce Secretary, registering their “deep concern,” and twelve states, including California and New York, said that they plan to sue the federal government over the move. Adding the citizenship question, Eric Schneiderman, the New York Attorney General, said, “will create an environment of fear and distrust in immigrant communities that would make impossible both an accurate census and the fair distribution of federal tax dollars.” He was reiterating a point that’s been made, repeatedly, by demographers, civil-rights advocates, and current and former government officials. Last November, a researcher at the Census Bureau named Mikelyn Meyers reported that there was an “unprecedented ground swell in confidentiality and data-sharing concerns among immigrants or those who live with immigrants.” In a presentation before the bureau’s National Advisory Committee, she described the panicked responses of immigrants who were afraid to answer survey questions in the current political climate, due to fears about deportation. “This behavior was an extreme departure from behavior that we have seen in the past,” she said. “This seems to be related to questions of legal residency or the perception that certain groups are not welcome.” By adding a citizen question to the census, the federal government may scare off residents from participating, and thus alter the results; that, in turn, could short-change future federal funding, and, if it caused district lines to be redrawn, cost Democrats congressional seats.

Ross, in his announcement, claimed that there was no solid evidence that the response rate would drop under the newly adopted policy, but the real burden is on him to explain why such a dramatic change is worth the risk. “When you do this once every ten years, for three hundred and forty million people, you’ve got to get it right,” one demographer told the Times. The last time the government asked whether respondents were citizens was in 1950. The question has come up since then, but only as part of a canvas called the American Community Survey, which is conducted on a rolling basis and has a smaller sample size. The results of this survey are widely seen as being sufficient to account for both the immigrant and the voting populations. “The courts are not complaining there’s a data problem,” Hasen told me.

So, who is complaining? One person seems to be John Gore, the acting head of the civil-rights division of the Justice Department. According to an investigation by ProPublica, late last year Gore drafted a proposal to add the citizenship question to the census. An attorney formerly with the firm Jones Day, Gore has been involved in Republican redistricting efforts for years in states such as Virginia, South Carolina, Florida, and New York. He has also defended Republican-backed voter-I.D. laws, including one effort, in 2012, to purge the Florida voting rolls of non-citizens, which had the effect of cancelling the registrations of some eligible voters, who were assumed to be foreign. An analysis conducted by the Miami Herald found that “Hispanic, Democrat, and independent-minded voters are the most likely to be targeted in a state hunt to remove thousands of non-citizens,” whereas “whites and Republicans are disproportionately the least likely to face the threat of removal.” The justification usually given for such measures is that ineligible voters might otherwise cast ballots illegally to sway the outcome of elections. Researchers and academics have categorically refuted these claims, and several state Republican officials have even admitted to drumming up the specter of voter fraud as a way to gain an edge over Democrats.

President Donald Trump has taken up the argument for a combination of personal and political reasons. After he lost the popular vote, in 2016, he claimed that three to four million undocumented immigrants had voted for Hillary Clinton. (“I won the popular vote if you deduct the millions of people who voted illegally,” he tweeted.) Once in office, to lend credence to his claims of mass voter fraud, Trump created the Presidential Advisory Commission on Election Integrity, naming Vice-President Mike Pence and Kansas Secretary of State Kris Kobach to head it. It disbanded in January, having proved nothing.

In the meantime, Republican officials sought to make examples of immigrants who had voted illegally, even if they’d done so unknowingly. Last year, in Texas, a thirty-nine-year-old mother of four from Mexico, who had voted in 2012 and 2014—because, as a green-card holder, she thought she could—was sentenced to eight years in prison; if her legal appeal fails, she will be deported after serving her time. In Kansas, a Peruvian mother of three who also had a green card voted in a local school-board election more than a decade ago, without realizing that she was not allowed to, and was deported after years of court battles. Isolated examples like these were supposed to be the “tip of the iceberg,” in the words of Kris Kobach, who has staked his career on devising onerous voter-I.D. requirements to combat a nonexistent problem. Earlier this month he was in federal court, in Kansas, defending himself against a lawsuit brought by the American Civil Liberties Union on behalf of the League of Women Voters and five Kansas voters. The groups argued that a 2011 law that he enforced in the state, which required that voters show proof of citizenship, may have cost up to thirty-five thousand eligible voters their ability to cast ballots in local, state, and federal races. A verdict is expected next month, but the trial was a disaster for Kobach, who presented questionable statistics and relied on cartoonishly incompetent experts.

What’s ultimately most striking about the Trump Administration’s efforts to retool the census is the transparency of its motives. They aren’t just political but existential. The new census question marks a return to a policy from the middle part of the twentieth century, which is roughly where the Administration’s immigration policies are designed to take us, too. For the first time in decades, an American President wants to halve the number of immigrants who come to this country legally each year. The model that Trump and his advisers seem to have in mind is that of the period prior to 1965, when immigration laws expanded to admit more immigrants from an increasingly diverse range of non-European countries. Since then, tens of millions of people have come to the United States to join the work force and start families. Their children (and their grandchildren) are citizens, who study in local schools and depend on local, state, and federal resources. There’s no more obvious sign of disdain for these lives than to accept that, when the government takes stock of who counts in the United States, they may not be included.