Citizenship lists that the Trump administration has ordered be compiled and shared with state election officials this year are likely to be incomplete and unreliable for determining voter eligibility, the Justice Department told a federal judge on Thursday.
The admission, in Federal District Court in Washington, came in a lawsuit challenging an executive order President Trump signed in March that would create state registries of citizens using federal data, and require the U.S. Postal Service to regulate mail-in voting.
The admission appeared to compound what Mr. Trump had already acknowledged could be legal troubles for the order, which is part of his sweeping attempt to bend election mechanics to his will. The Constitution does not give the president any explicit authority over elections, and Democratic-led states and organizations are turning to the courts to try to halt the efforts.
During the hearing on Thursday, Stephen M. Pezzi, a senior counsel at the Justice Department, told Judge Carl J. Nichols that it was too speculative to anticipate that states might seize on the lists to purge registered voters.
“No list is ever going to be perfect,” he said. “Certainly, a responsible state wouldn’t throw everyone who isn’t on the list off the voter roll.”
Mr. Pezzi allowed that it was possible that some states might be “overzealous” in checking the lists against their current registered voters, after Texas last year compared its voter rolls with federal data and started the process of removing roughly 2,700 voters deemed “potential noncitizens.”
But he said it was more likely that some states would ignore the lists altogether, while others might turn to them for help with “lawful purposes” such as “post-election law enforcement.”
Judge Nichols indicated he would release a preliminary decision shortly, and warned the government not to take steps on the order without updating the court.
Various Democratic organizations sued in April to stop the order from taking effect, calling it unconstitutional and arguing that using Social Security data and other federal resources to produce the lists violated federal privacy law. The case contends that Mr. Trump resorted to the order only after Congress failed to pass a broad package of other restrictions such as strict voter identification rules.
But Mr. Pezzi insisted on Thursday that the order did nothing more than take data already in the government’s possession to make it available to states.
“It’s not a list of people to be targeted,” he said. “It’s not a list of noncitizens.”
Lawyers representing the groups warned of an ungovernable election season if the order was not blocked, predicting county-level officials even in states that rejected the lists would feel a responsibility to turn potential voters away based on the names provided by the federal government.
Danielle Lang, a lawyer for the League of United Latin American Citizens, told Judge Nichols that the order was “drafted to cause maximum damage and chaos” and would coincide with primaries already underway in many states. She argued that the lists would invariably be incomplete and outdated.
“They’re going to be stale the very next day,” she said. “People move. People turn 18.”
Judge Nichols also pressed lawyers representing the Democratic groups, asking them to explain how states that decided to ignore the lists would be affected.
“Even in New York, I would bet top dollar that there are going to be local election officials” who act based on the lists, Ms. Lang said.
In an attempt to defer judgment, departments and agencies affected by the order submitted briefs to the court before Thursday’s hearing saying that their responses to the executive order were in preliminary stages.
For instance, the order directs the Postal Service to develop a protocol for sending only mail-in or absentee ballots of voters deemed eligible through the lists. But Steven W. Monteith, the Postal Service’s executive vice president, wrote in a declaration to the court that the agency was in the “deliberation phase” and had not “reached any final decisions about the substance of a proposed rule.”
Experts said a rollout of a new way of handling mail ballots mere months before a midterm election would itself create problems for the Postal Service.
If Mr. Trump’s order withstands legal challenges, “the Postal Service is going to be put into a challenging administrative role,” said Kevin R. Kosar, a Postal Service analyst at the conservative-leaning American Enterprise Institute. “It’s just going to put a lot of additional work on the agency, and it’s not clear that there’s going to be any resources provided to them for this purpose,” he added.
Also at stake is the service’s independence, which was established by the 1970 Postal Reorganization Act. “It’s independent; it has its own funding,” said James S. O’Rourke, an emeritus professor at the University of Notre Dame who has studied the Postal Service. “They’re not accountable to the president or to an executive agency.”
In an interview with The New York Times last month, Postmaster General David Steiner sidestepped questions about the service’s independence and said it would follow the executive order “unless a court tells us otherwise.”
