And despite Trump’s criticisms, states have numerous safeguards in place to protect against fraud in mail-in voting, and research indicates that instances of such fraud are exceedingly rare. Here’s what to know.

President Donald Trump cast a mail ballot in an upcoming Florida special election, according to Palm Beach County records, while publicly condemning the voting method as fraudulent."Mail-in voting means mail-in cheating.

GOP lawmakers are in a tough spot, with the president demanding that the Senate vote to end most mail-in ballots even though many red-leaning states have embraced them.

Because the vast majority of Californians vote by mail, the state stands to be disproportionately affected by new restrictions sought by President Trump.

An Arizona ballot initiative seeks to enshrine mail-in and early in-person voting in the state constitution. The Free, Fair and Secure Elections Act would guarantee Arizonans could vote in person on Election Day at county centers,

After going through a cooling off period, election denialism has come roaring back. It's fueling an attack on Washington's popular vote-by-mail system.