In some states voters could find themselves on the defensive if someone decides to challenge their right to vote on Election Day.
So-called citizen voter challenges — when a fellow voter can challenge the eligibility of another voter — are relatively rare and are separate from the trained election monitors you will see at some sites.
Voting experts don't expect such challenges to be widespread, but say anything's possible amid Donald Trump's call for supporters to watch for fraud.
Battleground states like Florida and Pennsylvania not only allow citizens to challenge the eligibility of other voters inside polling locations but place the burden of proof on the person who's challenged. In addition, a challenged voter in certain circumstances must cast a provisional ballot that may or may not be counted.