PORTLAND, Ore. (KATU) — Oregon and Washington joined a multistate lawsuit challenging a new U.S. Postal Service (USPS) rule that would impose federal requirements on mail-in voting ahead of the November midterm elections.

The lawsuit, led by the attorneys general of California, Massachusetts, Nevada and Washington, asks a federal court to block the rule while the case moves forward. The coalition includes 25 states and the District of Columbia, along with Pennsylvania’s governor.

According to the states, the rule would require them to submit lists of voters eligible to receive mail ballots to USPS. It also would create new ballot-envelope design standards that states would need to meet and receive USPS approval for.

The states say USPS would not deliver ballots to voters missing from its state-specific lists or ballots sent in envelopes that do not meet the new standards. The dispute centers on ballot delivery and envelope requirements, not how states count ballots.

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Oregon Attorney General Dan Rayfield and Washington Attorney General Nick Brown argue the requirements interfere with states’ authority to run elections and could create new administrative hurdles weeks before the general election season.

“The Constitution is clear: states control elections — not the president,” Brown said in a statement.

The lawsuit alleges the rule exceeds USPS authority, violates federal procedural and privacy laws and conflicts with voting-rights law. The states are seeking a temporary restraining order to prevent the rule from taking effect during the legal challenge.

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State officials say they would need to redesign ballot envelopes, build systems to send voter lists to USPS, train election workers and notify voters about the new procedures without additional resources. They also argue eligible voters could miss their ballots because of administrative mistakes or problems with what they describe as a rushed, untested system.