E.J. Dionne in WaPo:

All who rightly insist that remedying embedded racism and economic injustice requires both organized protests and election victories must reckon with this possibility: Election Day 2020 could be a catastrophic mess.

Whose interest would a chaotic election serve? The chaos president. President Trump would challenge the results of such an election if he lost, and he might win it by blocking enough of those who oppose him from casting ballots.

Last Tuesday’s primaries are a cautionary tale. They showed what can go wrong even in places that operate with the best will in the world.

Both the District of Columbia and Maryland hoped to push as much voting by mail as possible. It was an admirable instinct during a pandemic, but it didn’t work out so well.

Writing in Slate, Mark Joseph Stern called primary day in the nation’s capital “an unmitigated disaster.” The Post’s Julie Zauzmer, Jenna Portnoy and Erin Cox reported that many are calling for election officials in both D.C. and Maryland “to resign after botched delivery of absentee ballots and hours-long waits at polling places left some voters disenfranchised.”

A big problem in both places: Optimism about voting by mail encouraged election officials to slash the number of polling places and voting centers — in Washington from the normal 143 to a mere 20. In Baltimore, a city with 296 precincts, there were only six Election Day voting sites.

One more thing: Mail voting means that even efficient systems can take a long time to get to a final result. Mailed ballots typically count as long as they are postmarked on Election Day. This means votes are still flowing in a week or more after the election. Americans need to be prepared for the possibility that because of mail voting, we may not know the winner until well after election night. Forewarning is the vaccine against the virus of Trump’s voter fraud claims.