The U.S. Supreme Court on Monday rejected the Department of Justice’s emergency request to temporarily prevent California from counting mail-in ballots cast by about 20,000 voters whose citizenship the department questioned. The court issued a brief order without explaining its reasoning or noting any dissents, and did not ask California officials to respond before ruling.

The request came hours before the decision and on the eve of Election Day. It followed a ruling by the 9th Circuit Court of Appeals, which had rejected the DOJ’s effort to overturn a lower-court decision allowing the ballots to be counted.

The Justice Department sued California on Oct. 15, seeking to stop officials from tabulating ballots from people it described as likely noncitizens until their citizenship could be verified. Federal law bars noncitizens from voting in federal elections. The department had also provided Los Angeles County officials with a thumb drive containing names of voters it suggested might be noncitizens.

U.S. District Judge David Carter denied the DOJ’s request to set aside ballots associated with a list prepared by the Department of Homeland Security. The 9th Circuit later upheld that decision in a 2-1 ruling. The majority said granting the department’s request carried a material risk of disenfranchising voters.

In its Supreme Court filing, Solicitor General D. John Sauer said the government had identified more than 20,000 people who appeared, based on publicly available information, to be registered in California but were likely not U.S. citizens. He argued that the government was likely to prevail in its appeal and that challenged ballots could not be separated once mixed with valid ballots.

The Supreme Court’s decision came amid other election-related cases involving the DOJ. In a separate California case, a federal judge barred the department from threatening election workers with criminal prosecution for refusing to stop ballot processing or comply with other demands. During a hearing in that case, a DOJ lawyer acknowledged that lists of purported noncitizens on California voter rolls had a high error rate, according to MS NOW.

The department is also appealing the dismissal of a lawsuit seeking to prevent Alaska officials from immediately certifying the U.S. Senate election result if incumbent Republican Sen. Dan Sullivan loses by a margin potentially attributable to voter confusion over another candidate with the same name.

Sources: CNBC Markets.