In an emergency request on Thursday, the Justice Department asked the Supreme Court to lift Boston-based US District Judge Indira Talwani's order temporarily preventing the USPS from enforcing the new rule, which it adopted following an executive order by the Republican president to restrict mail-in ballots.
The USPS regulation would impose new voter-specific data and ballot envelope standards, and potentially refuse the delivery of ballots that do not comply, which critics say could disrupt thousands of legitimate votes as the November 3 vote approaches.
Republicans are locked in a tight battle to retain control of Congress in the election. Critics say restricting mail-in ballots would stand to disproportionately benefit Republicans given that Democratic voters traditionally have been more likely to use mail-in ballots.
It is the second time that the administration has turned to the Supreme Court as it defends Trump's directive against legal challenges by states and voting rights groups. On August 24 the court lifted an earlier injunction imposed by Talwani in June blocking Trump's order.
That decision, powered by the court's 6-3 conservative majority, faulted a coalition of mostly Democratic-governed states for suing too soon, but left the door open to another challenge. The court's three liberal justices dissented.
Under the new USPS rule, states must provide lists of mail ballot recipients to the postal service and use agency-approved outbound and return ballot mail envelopes outfitted with unique barcodes.
The postal service could then refuse to send out ballots that do not comply with the new standards or are associated with voters who do not appear on the lists.
Trump, who signed his executive order targeting mail-in ballots in March, has for years cast doubt on their security, although evidence of voter fraud is rare. Trump has lied about widespread fraud in US elections including his 2020 loss to former Democratic president Joe Biden.
The administration in its written filing urged the Supreme Court to allow it to implement an "important federal policy to protect the mails from being used to commit voter fraud".
A coalition of mostly Democratic-governed states and Washington DC, as well as a number of voting rights groups, challenged the new USPS rule.
Talwani issued a temporary order on August 27 blocking the rule for 14 days, finding that it likely violates the US Constitution, under which the states administer elections, and would be impossible for the states to comply with given the rapidly approaching midterms.
The Justice Department asked the Boston-based 1st US Circuit Court of Appeals to put the judge's order on hold, but did not wait for a decision before turning to the Supreme Court.
Talwani also held a hearing on Thursday to consider whether to issue a longer-term injunction.
