The US Supreme Court has declined an emergency request from the Trump administration, refusing a bid to force California election officials to set aside more than 20,000 mail-in ballots.

Filed by Solicitor General D. John Sauer just one day ahead of the midterm elections, the Department of Justice petition asked the high court to segregate the ballots out of concern they may have been issued to non-citizens. The emergency application argued that separating the votes was necessary because once ballots are commingled, the administration's legal challenges could not effectively unwind them.

Lower courts had previously rejected the DOJ's demands to intervene in the state's voting process, with one judge characterizing the attempt as pre-election interference. The Supreme Court's refusal to take up the request marks the latest judicial setback for the administration's efforts to alter election administration procedures across multiple states.