Washington mail-in voting at risk as Supreme Court signals major ruling before November

The U.S. Supreme Court appears poised to invalidate laws in 29 states, including Washington, that allow mail-in ballots postmarked by Election Day to be counted if they arrive afterward, a decision that could dramatically reshape voting procedures by November.

Former Washington State Attorney General Rob McKenna says the court’s conservative majority seemed sympathetic to challengers in a Mississippi case that could force all mail-in ballots for federal races to be physically received by Election Day. The court heard arguments in the case on Monday.

“A majority of the court appeared to be sympathetic to the challengers, and they may overturn Mississippi’s law, which would mean that mail-in ballots for federal elections have to be received by Election Day to be valid,” McKenna told “Seattle’s Morning News.”

Republican, Libertarian parties lead challenge

The case stems from a challenge by Mississippi’s Republican and Libertarian parties to a law adopted during the COVID-19 pandemic. Like Washington, Mississippi requires ballots to be postmarked by Election Day but accepts them if they arrive afterward.

McKenna said a ruling against mail-in voting could take effect almost immediately.

“Elections in November, you guys issue your decisions in late June or early July,” McKenna said, referencing comments made during oral arguments. “So I think there would be a lot of scrambling by states that allow mail-in voting to make it clear to folks that their ballots have to be received by Election Day.”

The potential ruling raises complicated questions about how ballots containing both federal and state races would be handled. McKenna said late-arriving ballots would likely see only federal race votes discarded.

“Your votes in the non-federal races, including on statewide ballot measures, local offices, state legislator races, those would be counted,” McKenna said. “But your votes, if the ballot was received after Election Day, in the races for Congress or in Senate races would not be counted.”

President Donald Trump has long criticized mail-in voting, recently stating, “Mail-in voting means mail-in cheating.” However, Trump himself voted by mail in Florida this week.

McKenna questioned the consistency of Trump’s position.

“It seems to be that President Trump thinks mail-in voting creates an advantage for Democratic candidates,” McKenna said. “Look at Mississippi, it’s a deep red state. He carried it by a wide margin. Little hard to understand how mail-in voting hurts him there.”

McKenna noted that Trump “won the election in 2016 and again in 2024 and didn’t seem to think there was any cheating going on there, including ballots that were mailed in.”

Military, overseas voters most affected

The ruling could significantly impact military personnel and Americans living overseas, who cannot easily access ballot drop boxes.

“There’d be a real impact on military voters overseas,” McKenna said. “They obviously can’t drive down to the corner and drop off [their ballots.]”

McKenna urged Washington Secretary of State Steve Hobbs to begin preparing immediately.

“I think they better be preparing a public communications program to let voters know that if their ballot has federal races on it, they better get it in by Election Day,” McKenna said.

While Congress has authority under the Constitution to alter state regulations governing federal elections, McKenna noted the bill currently pending would codify the requirement that ballots be received by Election Day rather than protect current practices.

McKenna pointed to a historical precedent in Washington when the state’s blanket primary was struck down, resulting in more than 100,000 ballots with improperly cast partisan votes. In that instance, votes in non-partisan races and ballot measures were still counted.

“I think the Republic will survive this as well,” McKenna said. “But I do think that it’s a complication. And this could result in a lot of votes in the federal races not being counted.”

The Supreme Court is expected to issue its ruling by late June or early July.

Manda Factor is the host of “Seattle’s Morning News” on KIRO Newsradio. Follow Manda on X and email her here. 

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