The latest method of voting to fall into the political crosshairs is the way overseas voters - including members of the military stationed abroad - cast their ballots.
The process is governed by federal law and implemented by states. In recent weeks, Republicans have been challenging how states handle these voters, something former President Donald Trump didn't do in 2020 when he and his allies challenged his loss in court.
But things have changed, with just a month before Election Day and a tight race between Trump and Vice President Kamala Harris. It's part of a broader legal strategy by Republicans to position themselves for post-election challenges should Trump lose.
Ballots already have been sent to overseas and military voters under a federally mandated deadline. Trump and his Republican allies contend these ballots could be part of an elaborate scheme to steal the election from him, a claim for which there is no evidence. Their challenge comes as the voters who receive the ballots are increasingly from groups that are presumed to be Democratic.
Here's a look at the issues involved and what's driving the claims.
