The Supreme Court on Monday rejected the Trump administration's emergency appeal to force California election officials to set aside mail ballots from more than 20,000 voters whom federal authorities identified as likely noncitizens.

The one-sentence order came hours after the Justice Department filed the request and carried no noted dissents from the justices. It upheld lower court rulings that blocked the federal effort to segregate the ballots pending verification of citizenship status.

The administration had argued that the Department of Justice identified the individuals through public records as people who appear registered to vote in California but are likely not U.S. citizens. Officials sought a limited injunction to prevent those ballots from being commingled with others until eligibility could be confirmed, framing the request as a modest step to protect election integrity ahead of the midterm elections.

Lower courts, including a federal district judge in California and a divided panel of the 9th U.S. Circuit Court of Appeals, ruled against the administration. Those decisions emphasized state authority over election administration under the Constitution's Elections Clause and raised concerns about the accuracy of the federal list and potential disenfranchisement of eligible voters.

The Supreme Court action caps a series of setbacks for the administration's legal campaign targeting suspected noncitizen voting in California. A separate federal judge in Washington also ruled Monday that certain last-minute demands on state officials likely violated constitutional principles reserving election rules to the states and Congress.

California officials have maintained that the federal list contains substantial inaccuracies and accused the effort of undermining public confidence in the process. The ballots in question involve mail votes that some lower courts noted may already have been processed.

The ruling leaves intact California's procedures for counting the challenged ballots while the administration continues broader efforts to enforce federal prohibitions on noncitizen voting through other avenues.