A US judge on Thursday declined to block President Donald Trump’s executive order tightening rules on mail-in voting in a loss for the Democratic Party, whose lawyers argued that it could disenfranchise millions of voters.

The decision comes as Trump’s Republicans are locked in a tight ​battle to keep control of both houses of the US Congress in the November midterm elections. Trump has ​for years pushed the false claim that his 2020 election defeat was the result of ⁠widespread voter fraud and has criticised voting by mail.

The executive order signed by Trump on March 31 directed his administration ​to compile a list of confirmed US citizens eligible to vote in each state and to use federal data ​to help state election officials verify who is eligible to vote.

It also required the US Postal Service to only deliver ballots to voters on each state’s approved mail-in ballot list, and required states to preserve election-related records for five years.

Judge says Democrats’ challenge is premature

In rejecting a request by plaintiffs including Senate Minority Leader Chuck Schumer of New York that he issue a ​preliminary injunction blocking the measure, Washington-based US District Judge Carl Nichols wrote that the Democrats had brought the case too early because ‌the ⁠government had not yet produced any flawed citizenship lists and the Postal Service had not yet implemented any new rules.

“Given that the Executive Order does not command Plaintiffs to do anything, and that no agency has yet acted pursuant to the Order in a way that could harm Plaintiffs, they have not suffered any harm at present,” wrote Nichols, ​who was appointed by Trump ​during his first term.

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The ⁠judge said the Democrats could ask for an injunction again after federal agencies took steps to implement the executive order.

Hearing next week in parallel case

Democrats had argued that the ​order infringed on individual states’ rights to regulate elections under the US Constitution.

They said ​the executive order’s ⁠direction that agencies use Department of Homeland Security and Social Security Administration data to build “state citizenship lists” risked improperly excluding lawfully registered voters because the data sources can be out of date and may include errors.

The Justice Department countered that ⁠the litigation ​was premature.

A coalition of Democratic states brought a similar lawsuit challenging the ​executive order in federal court in Boston. US District Judge Indira Talwani, an appointee of Democratic former President Barack Obama, is due to hear ​arguments in that case on June 2.