During the early voting period, disagreements over masks occasionally led to long voting lines and had election officials clearing polling sites for the mask-less or directing them to stations away from other machines.
Still, due to the decentralised nature of the country's voting systems, rules are different depending on where ballots are cast. Some places are taking harder stances than others.
In one case that caught national attention, a Maryland man was arrested after refusing to wear a mask while trying to vote last month. He has since sued his local election board over the incident.
In Texas, the issue has wound up in court.
First, Republican Governor Greg Abbott carved out an exception for voting locations in his statewide mask mandate issued earlier this year. Then, in response to a challenge from voting rights groups, a federal judge ordered that masks must be worn inside polling sites. That decision was quickly reversed by an appeals court.
Despite the legal back and forth, at least some Texas elections administrators had chosen not to enforce the short-lived polling station mask mandate.
Wendy Weiser, director of the democracy programme at the Brennan Centre for Justice, said governments should be able to require masks at polling places during the coronavirus pandemic.
"Despite the few attempts to challenge mask requirements in court, there is no question that it is well within the legal authority of states and localities to require masks to be worn at polling places — both as a matter of public health and as a reasonable regulation of the election process," she said.
Most places have settled on a strategy of strongly encouraging voters to wear masks. Their message is that abiding by widely accepted health guidelines will protect poll workers and other voters.
In Atlanta, Mayor Keisha Lance Bottoms signed an extension of measures designed to limit the spread of the virus, including a mask mandate in the city. But her order specifically says "no individual shall be denied ingress or egress to or from a polling place for failure to wear a facial covering or mask."
Gabriel Sterling, statewide voting system implementation manager for the secretary of state's office, said that individual poll managers will have to decide how to accommodate people who have tested positive or are in quarantine.
He suggested that one way to handle them might be pulling them aside and having them vote a hand-marked paper ballot away from everyone else, rather than having them use one of the touchscreen voting machines.
But he stressed that no additional barriers to voting can be put in place.
"You can't turn away somebody because they're not wearing a mask," Sterling said.
In Florida's Broward County, where there is a mask ordinance, elections spokesman Steve Vancore said just four out of 364,000 early voters refused to wear masks. They were allowed to cast ballots after they were separated from other voters.
"We tell them 'Sir or ma'am – it is mostly sir – you are not supposed to be in here without a mask. There is a county ordinance," he said. "They mostly obey."
- AP