Judge Declines, for Now, to Block Mail-In Voting Changes Ordered by Trump

A federal judge on Thursday declined, for the moment, to block an executive order President Trump signed in March targeting mail-in voting and directing the creation of a federal database of citizens to help guide states on voter eligibility.

The decision allows the Trump administration to continue pursuing measures to insert the federal government into the administration of elections that are otherwise managed by the states. The administration has proposed changes at the Postal Service and having the Homeland Security Department compile state-by-state voter lists using Social Security data and other information drawn from federal databases.

In a 26-page opinion, Judge Carl J. Nichols wrote that it was premature for the court to intervene. He found that the Trump administration had yet to carry out much of the order, leaving most of the harms predicted by the lawsuit still hypothetical. He added that if evidence emerged that the changes were burdening state officials or sowing confusion, the Democratic-aligned groups who have sued to block the order could return to court.

“The court recognizes that the Postal Service may ultimately issue a final rule that directly affects plaintiffs or their members, or that the government may develop state citizenship lists that omit specific individuals due to particularized flaws,” he wrote. “Plaintiffs may, of course, renew their motions if and when those future actions occur.”

The ruling came as the Trump administration has moved aggressively since last year to compile voter roll data at the national level over the objections of state officials and voting rights organizations. Several federal judges have struck down efforts by the administration to request voter information from the states.

A group of Democratic organizations and lawmakers had sued to stop the executive order, arguing that it was a violation of federal privacy law to compile a centralized database of eligible voters and also unlawful interference in state elections to circulate that data among local officials. The case combined three separate lawsuits brought by groups including the N.A.A.C.P., the League of United Latin American Citizens and the Democratic Senatorial Campaign Committee, and included Senator Chuck Schumer and Representative Hakeem Jeffries, the Senate and House minority leaders.

During a hearing in May, lawyers representing the Democratic groups told Judge Nichols, a Trump appointee, that the risks of abuse were significant. They painted a dark picture of the coming election season, arguing that the Trump administration appeared intent on injecting chaos into the system and empowering low-level officials to act on the administration’s behalf in policing elections.

The groups emphasized that the federal voter list, if created, would most likely be prone to outdated or faulty data, and warned that local officials could use the list to improperly disenfranchise legal voters. They also warned that the order would direct the Postal Service to work outside its legal mandate under the law, forcing it into new a role monitoring voting.

In court, the Justice Department appeared to partially acknowledge those concerns, telling Judge Nichols the lists were envisioned more as reference material for state election boards and acknowledging they would not be an exhaustive or up-to-date registry of valid voters.

Stephen M. Pezzi, a Justice Department lawyer, said the government was still working to evaluate the order and had not started gathering the data it envisioned. Mr. Pezzi agreed to a request from Judge Nichols to inform the court if the government began taking steps to assemble the lists.

But Todd Blanche, the acting attorney general, appeared to contradict that position during Senate testimony in May, indicating the Justice Department was actively working with the White House to carry out the order.

A department spokesman did not immediately respond to a request for comment about Mr. Blanche’s testimony.

“It’s working with other agencies within the administration to implement the goals,” he said. “I think they are appropriate goals to make sure that we have free and fair elections, to make sure that those are implemented, whether it’s the D.O.J. that needs to implement them or some other federal agency.”

In the order on Thursday, Judge Nichols appeared inclined to give the administration the benefit of the doubt until there were more concrete details about the lists. He wrote that it remained to be seen what state election officials might use them for, but that it was not clear the federal government’s compiling them was inherently unlawful.

“The order does not mandate any action by a state once a list has been transmitted to it, and in any event, no infrastructure for compilation or transmission of the lists has been established; no list has been created or transmitted; and no state has taken any action with respect to any list,” he wrote.

When Mr. Trump signed the executive order in March, he mused that the order could face legal challenges, but said he thought it was “foolproof.”

“You may have to find a rogue judge,” he said while showing the signed order to journalists. “That’s the only way that can be changed.”

The order requires the Postal Service to take its first steps to complying by May 30, issuing notice by that day of a rule-making process to adopt the changes.

Mr. Trump has also called on the Postal Service to deliver only ballots of voters deemed eligible. Postal and election experts denounced that as an illegal overstep of presidential authority.