Pro-voter groups asked a federal appeals court to keep a USPS mail voting rule frozen, arguing it oversteps congressional authority and would hinder ballot transmission.

A whistleblower leveled allegations that the USPS is rushing the portal under a harsh zero-percent failure policy that could lead to thousands of ballots being rejected for simple errors.

States have begun mailing or are preparing to mail mail ballots, with North Carolina already sending ballots as many others prepare, complicating compliance under the tightened rules.

The groups, including the League of Women Voters of Massachusetts, contend the rule functions as a barrier to ballot transmission rather than a mere technical design change.

They invoke the major questions doctrine, arguing the rule lacks explicit congressional authorization and could constitute constitutional overreach into state election processes.

The Justice Department is appealing to the Supreme Court to reinstate the rule, saying it would be functional in time for elections even as the portal remains incomplete or uncertain.

Pro-voter groups argue that lifting the block would disrupt state election operations and note no demonstrated irreparable harm or clear benefit for the upcoming November elections.

The rule would require states to adopt specific mail ballot envelope designs and upload voter data to a federal portal for ballot clearance, a move already halted by a district court as potentially unconstitutional and disenfranchising.