WASHINGTON - US President Donald Trump on Tuesday signed an executive order to reshape mail-in voting and expand federal involvement in voter eligibility, a move expected to face swift legal challenges.

The order directs the Department of Homeland Security, in coordination with the Social Security Administration, to compile state-by-state lists of confirmed US citizens aged 18 or older and provide them to state election officials, according to the White House.

It also instructs the US Postal Service to limit the delivery of mail-in and absentee ballots to voters included on state-approved lists and to require the use of official election mail envelopes with tracking barcodes.

Legal experts and election officials said the order is likely unconstitutional, as the US Constitution grants states primary authority over administering elections, while Congress sets certain federal rules.

Voting rights groups and Democratic state officials quickly signaled plans to challenge the order in court.

The directive is the latest in a series of efforts by Trump to alter election procedures. In 2025, he signed an executive order aimed at tightening voter registration requirements and restricting the counting of late-arriving ballots, though key provisions were blocked by federal courts.