Barriers to voting can take many forms.

Sometimes those barriers make voting harder, as in reduced polling hours or restrictive photo-ID laws. Other times, they are administrative practices, such as unnecessary voter-roll purges.

Yet some of the most difficult barriers to overcome can be those caused by events entirely unrelated to voting.

Sept. 11, 2001, was Election Day in New York City. In the hours following the attacks, then-Gov. George Pataki canceled the elections, all votes were voided and new primaries were held two weeks later. When Hurricane Sandy struck the East Coast a week before the 2012 election, New Jersey allowed some voters to vote by email and fax. Hurricane Michael in 2018 caused Florida to waive various early voting restrictions to ensure that citizens of eight counties could cast their ballots.

None of these disasters, devastating as they were, posed the same threat that the novel coronavirus does for the 2020 election. Unlike prior events, the virus poses a health risk to voters in every state, city, town and village in the country. Not only will voters not want to wait in line and file into schoolrooms in proximity to others, but election workers – many of whom are elderly – also may not eagerly sign up to staff polling places where they will come in contact with hundreds of strangers in a single day.

Over the past few days, the most discussed solution has been for states to expand the use of absentee and vote-by-mail ballots. But with the exception of a handful of states, such as Colorado, Oregon and Washington state, most still rely primarily on in-person voting. For absentee voting to be effective for November, states must start planning now.

It will not be enough for states to simply allow more citizens to vote by mail. Each state must also provide adequate resources for the printing and distribution of millions of extra ballots and to support with extra funds the officials who are tasked with processing and counting the flood of mailed ballots. It will also require states to revisit their laws to provide free postage and community ballot collection. States then need to address the manner in which ballots are verified to minimize rejections based on issues with voters’ signatures.

Most important, for this system to work, states must be prepared to process and count the avalanche of ballots that will be postmarked by Election Day but arrive at election offices in the days afterward. A push toward voting by mail will flood postal facilities with a surge of last-minute mail-in ballots. Post offices will have to handle these while dealing with the effects of COVID-19 on their own workforces. Mail delivery times will grow in the wake of the pandemic, and frustrations will mount. Without careful and realistic planning, confidence in the system will fall.

That means that all votes postmarked by Election Day must be treated as timely and counted in full. Unfortunately, many states (including Maine) do not currently count ballots received after Election Day, regardless of when voters mail them.

These laws are profoundly unfair to voters who did everything right but whose ballots were delayed because of the post office. Such laws undermine public confidence in elections and are among the reasons many voters insist on voting in person.

The data show that the laws also affect minority voters most severely. In Arizona’s Maricopa County, for example, the Election Day deadline is four times more likely to disenfranchise Hispanic voters than white voters, and 5.5 times more likely to disenfranchise Native American voters than white voters. In Arizona’s Santa Cruz County, where 83 percent of the population is Hispanic, ballots are about six times more likely to be rejected than are ballots in Maricopa, with a 31 percent Hispanic population.

With Michigan and Pennsylvania encouraging vote by mail for the first time, we can expect to see similar problems. In Pennsylvania, 94 percent of all of the absentee ballots it rejected in 2018 were thrown out because of the state’s restrictive Election Day receipt deadline. The corresponding proportion for Michigan’s was 37 percent.

Replacing Election Day receipt laws with the more intuitive postmarked-by-Election Day standard is essential. Ideally, states will act to correct these anti-democratic laws. If not, Congress should step in and amend federal law to make clear that ballots mailed by a voter on or before Election Day must be treated as cast on Election Day.

Otherwise, it will again be left to the courts to protect the rights of voters. We must all make sure that the barriers to voting by antiquated voting laws are not raised higher by the coronavirus. The time to act is now.