WASHINGTON  — California and 22 other Democratic-led states urged the Supreme Court on Monday to block President Trump’s plan to take control of voting by mail through the U.S. Postal Service.

They said it is too late in the election year to impose a new set of regulations for mail ballots.

Doing so, they said, would lead to mistakes, including eligible and registered voters being told they are not on the federal government’s approved list.

“Because of the high risk of errors and the limited window for correcting mistakes, many of the millions of voters who rely on mail voting — especially voters with disabilities and those in rural areas — would likely be denied mail ballots and disenfranchised,” they told the court.

More broadly, they argued that the Constitution “entrusted the states and Congress — not the president — with the responsibility to set rules for federal elections.”

The justices are likely to act in a few days on whether to allow the Trump administration‘s plan to proceed pending the adoption of new and detailed guidelines.

Last week, Trump Solicitor Gen. D. John Sauer sent an emergency appeal to the Supreme Court contending judges in Boston moved too quickly to halt the administration’s new federal restrictions on voting by mail.

He argued judges should stand back for now, even though the midterm elections are only three months away.

Trump’s executive order required the U.S. Postal Service to use state-by-state lists of eligible voters who may send a ballot by mail.

Until now, states have had the constitutional authority to register voters for federal and state elections. And nearly a third of Americans now vote by mail.

Trump, however, has insisted that voting by mail leads to fraud, including by allowing noncitizens to vote.

Congress has refused to adopt new voting restrictions at Trump’s behest.

Instead, he issued an executive order on March 31 to enlist the Postal Service and the Department of Homeland Security to ensure “citizenship verification and integrity in federal elections.”

The order called on Homeland Security to compile state-by-state lists of citizens who are eligible to vote. And it told the postal service that it must use those lists to restrict who may vote by mail.

“The USPS shall not transmit mail-in or absentee ballots from any individual unless those individuals have been enrolled on a State-specific list,” the order said.

But a federal judge and the 1st Circuit Court in Boston ruled Trump’s new regulations may not be enforced this year, at least in the 23 Democratic-led states which sued.

On Monday, they told the court that USPS delivered nearly 100 million mail ballots to or from voters in 2024, with roughly 30% of all voters nationwide casting ballots by mail.