WASHINGTON — Congressional Democratic leaders sued to block President Donald Trump from prohibiting mail-in voting for anyone not on a preapproved list of citizens to be compiled by the Department of Homeland Security.

Top Democrats in the House and Senate, along with their campaign committees and the Democratic National Committee, allege that executive order issued Tuesday by the president “dramatically restricts the ability of Americans to vote by mail, impinging on traditional state authority,” according to the complaint filed late Wednesday in Washington federal court.

Under Trump’s order, the U.S. Postal Service would be banned from sending mail-in ballots to anyone not on the list of U.S. citizens.

The White House did not immediately respond to a request for comment Wednesday night.

The DHS would compile the list using citizenship, Social Security and other government records, according to the executive order. Also under the order, the U.S. attorney general is instructed to prioritize prosecution for any state election official who provides a ballot to an ineligible voter.

The order is Trump’s latest effort to alter elections since his defeat by Joe Biden in the 2020 presidential election.

For years, Trump has claimed — without evidence — that there is widespread fraud, including non-citizen voting, in U.S. elections. Trump’s Save America Act, which is stalled in the Senate, would require voters to show proof of citizenship when registering to vote.

In their suit, the Democrats say Trump is trying to “impose radical changes” that only states have the constitutional authority to make. Trump’s proposed changes “imminently threaten to disenfranchise lawful voters and plainly exceed the president’s lawful authority,” according to the complaint.

Before Wednesday’s suit, Arizona Secretary of State Adrian Fontes, a Democrat elected to his post in 2022, said his office would fight the order to protect the state’s mail-in voting system, used by 80% of voters.

“Arizona operates as the gold standard for election administration, requiring documented proof of citizenship (DPOC) at the time of registration and voter ID at the polls,” Fontes said. “This Executive Order is a disgusting overreach from the federal government.”

Oregon Attorney General Dan Rayfield, another Democrat, said in a statement his office would use every legal tool available to fight the order.

“Oregonians have been voting by mail for decades,” Rayfield said. “It’s safe and secure. Even the president does it.”

The case is DSCC v. Trump, 26-cv-01114, U.S. District Court, District of Columbia (Washington).

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(With assistance from Courtney Subramanian.)

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