President Trump's executive order seeking broad changes to how elections are run in the U.S. holds the potential to reorder voting, even as it faces almost certain litigation.

President Donald Trump issued a sweeping executive order this week calling for changes to U.S. elections, including requirements for people to prove citizenship when registering to vote and to have ballots be cast and received by Election Day.

Trump has signed an executive order requiring documentary proof of citizenship to register to vote in federal elections and mandating that all ballots be received by Election Day.