Manatt Files Amicus Brief in Supreme Court Case over USPS Election Mail Rule on Behalf of Leading Legal Scholars

On September 8, 2026, Manatt submitted an amicus brief in the U.S. Supreme Court on behalf of leading constitutional law and remedies scholars Edward B. Foley, Richard L. Hasen, Pamela S. Karlan and Douglas Laycock in United States Postal Service, et al. v. State of California, et al., No. 26A305, a closely watched emergency application concerning new USPS requirements for mail-in ballots ahead of the 2026 midterm elections.

The brief, prepared by a Manatt team led by Partner and Associate , in collaboration with Professor Hasen and Shelby Wayment of UCLA School of Law’s Safeguarding Democracy Project, argues that the Supreme Court can deny the government’s stay request without reaching the merits of the case. Amici write that “the Applicant’s asserted irreparable injury is so speculative and weak—and the balance of the equities and the public interest so one-sided in favor of Respondents and the public—that the Court may deny a stay in its judicial discretion without undertaking an in-depth consideration of the constitutional and statutory merits questions presented.”

The case arises from the federal government’s request that the Supreme Court stay the U.S. District Court for the District of Massachusetts' injunction currently blocking USPS from implementing new mail-ballot requirements. The challenged rule would require states to use USPS-approved ballot envelopes containing Intelligent Mail barcodes and to upload voter-registration data into a new USPS verification portal before election materials could be mailed. 

The brief goes on to explain that allowing the USPS rule to take effect weeks before the election would create significant disruption for election administrators and voters. Many states have already printed ballot materials or begun mailing ballots and would be unable to redesign envelopes, obtain USPS approvals and integrate new verification processes in time for the election. Amici explain that implementing the rule at this stage could result in rejected ballots, administrative confusion and potential disenfranchisement of voters who rely on mail voting, including elderly, disabled, rural, military and other absentee voters.

Read the full amicus brief .