I have written this oped for the New York Times. It begins:

The threat to the 2020 election’s legitimacy finally broke through into everyday conversation last week. People who pay little attention to politics started talking about whether President Trump was looking to mess with the United States Postal Service to slow down the receipt of mail-in ballots.

Mr. Trump was not shy about it. He told Maria Bartiromo on Fox Business Network last Thursday that he was pushing back against Democrats’ demand for further U.S.P.S. funding in the latest Covid-19 relief bill: “Now they need that money in order to have the post office work, so it can take all of these millions and millions of ballots …. But if they don’t get those two items, that means you can’t have universal mail-in voting, because they’re not equipped to have it.”

While targeting the U.S. Postal Service may be new, the threat to election integrity coming from Mr. Trump is not. But there are steps we can take right now to assure a fair election in November.

Mr. Trump has made at least 91 attacks on the integrity of voting so far this year (and more than 700 since 2012) and backed up his complaints about mail-in ballots with lawsuits in Pennsylvania, Nevada and Iowa. He has repeatedly tweeted the unsupported claim that increased use of mail-in ballots in November, necessitated by the Covid-19 pandemic, will lead to voter fraud and a rigged election.

Back in May he wrote that “There is NO WAY (ZERO!) that Mail-In Ballots will be anything less than substantially fraudulent. Mailboxes will be robbed, ballots will be forged & even illegally printed out & fraudulently signed….” He said that with Gov. Gavin Newsom of California sending ballots to all active registered voters, which he terms “universal mail-in” voting, “This will be a Rigged Election. No way!”

The end game here is a bit curious because Republicans traditionally have relied on mail-in balloting to get out the vote, and there are already signs that Republican turnout might be hurt by his rantings. How else to explain the president seeking to distinguish between good “absentee” voting and bad “mail-in” balloting and urging Floridians to vote by mail? And how else to explain the president not only repeatedly voting by mail but using a third person — what Mr. Trump refers to as “ballot harvesting” — to deliver his own ballot to election officials in the Florida primary on Tuesday?

The most benign explanation for Mr. Trump’s obsessive focus on mail-in balloting is that he is looking for an excuse for a possible loss to his Democratic opponent, Joe Biden, in November. The less benign explanation is that he is seeking to sow chaos to drive down turnout and undermine the legitimacy of the election, laying the groundwork for contesting a close election if he loses. I fear that the latter explanation is correct, and that makes it all the more urgent that election administrators, the media and others take steps to avoid a crisis of confidence in the 2020 election results.