California and nearly two dozen other states warned the U.S. Supreme Court on September 9, 2026, that allowing the U.S. Postal Service (USPS) to implement new rules for mail ballots could lead to significant disruptions and disenfranchise millions of eligible voters. The states argued that compliance with USPS's rules would be impossible ahead of the midterm elections, potentially preventing millions from voting by mail. They expressed concerns that the changes would create chaos in the voting process, particularly in states like North Carolina and Wisconsin, which have already begun mailing ballots.
The coalition, led by Democratic states including California, 23 others, and the District of Columbia, cited objections from various state and election officials, including those from conservative states like Utah, who described the implementation of the new rules as likely to be disastrous. Similar concerns have been raised by officials in Florida, Ohio, Texas, and Wisconsin.
The new rules, developed in response to a March executive order from President Trump, require states to submit complete voter lists to the Postal Service and adopt new ballot envelopes with individualized voter bar codes. The rules also mandate that the Postal Service reject any mail ballots that do not match these lists. Trump's order directed the Department of Homeland Security to create a list of eligible voters to compare against state lists.
Supporters of the changes, including officials from Republican-led states, argue they are necessary to prevent voter fraud. However, elections experts have stated that there is no evidence of widespread voter fraud, despite extensive audits.
The Democrat-led states have filed lawsuits to block the changes, claiming that neither Trump nor the Postal Service has the authority to regulate state-run elections and that the new rules would illegally prevent eligible voters from casting ballots. Independent voting rights groups have also filed lawsuits, alleging that the rules threaten to disenfranchise voters and hinder efforts to educate them about their voting options.
A Postal Service whistleblower has raised doubts about the agency's ability to implement the new rules effectively, claiming that the online portal for verifying ballots is flawed and could reject thousands of ballots. Last week, U.S. District Judge Indira Talwani granted a preliminary injunction halting the implementation of the new rules nationwide.
The Trump administration has appealed this ruling to the Supreme Court, arguing that the states' concerns are unfounded and represent an overreach of federal authority. Solicitor General D. John Sauer contended that the new rules do not dictate how states administer elections but impose reasonable requirements for election-related mail. He argued that not allowing the changes would cause serious harm to the federal government and the voting public.
Experts have consistently rejected claims of potential harm from the new rules, stating that the administration has not provided evidence that the changes would effectively address voter fraud. They noted that the Postal Service is not prepared to implement the new rules accurately and efficiently, which could disproportionately affect vulnerable populations reliant on mail voting.
The Democrat-led states have emphasized that the Trump administration has not proven that widespread voter fraud is a legitimate concern but has demonstrated its own lack of preparedness to implement the changes without causing disruption. A ruling from the Supreme Court is anticipated, given the emergency nature of the appeal.