President Donald Trump’s executive order seeking broad changes to how elections are run in the U.S. is vast in scope and holds the potential to reorder the voting landscape across the country, even as it faces almost certain litigation.

He wants to require voters to show proof that they are U.S. citizens before they can register for federal elections, count only mail or absentee ballots received by Election Day, set new rules for voting equipment and prohibit non-U.S. citizens from being able to donate in certain elections.

A basic question underlying the sweeping actions he signed Tuesday: Can he do it, given that the Constitution gives wide leeway to the states to develop their own election procedures? Here are some of the main points of the executive order and questions it raises.

Voters would need to provide citizenship documents to register Trump’s order calls for the federal voter registration form to be amended so prospective voters must provide documentary proof of citizenship, such as a U.S. passport or a birth certificate.

It also says states should turn over their voter lists and records of voter list maintenance to the Department of Homeland Security and the Department of Government Efficiency for review, and directs federal agencies to share data with states to help them identify noncitizens on their rolls.

If states refuse to collaborate with federal law enforcement to prosecute election crimes, they could potentially lose out on federal grants, the order says.

Noncitizen voting, which is already a felony in federal elections that can lead to prison time and deportation, is exceedingly rare. Still, Trump falsely claimed in 2024 that it might happen in large enough numbers to sway the outcome of the presidential race, and it has been a top conservative priority in recent months.

Republicans have been trying to get a documentary proof of citizenship requirement through Congress, a goal this order seeks to accomplish. Voting rights groups have expressed concern about such a requirement, saying it could disenfranchise the millions of Americans who do not have proof of citizenship readily available.