The Trouble With Mail-in Voting Might Not Be Fraud, But Government Incompetence

President Trump has repeatedly warned of potential voter fraud associated with mass mail-in ballots for the November election, but a bigger threat might be sheer incompetence. Can we really rely on the U.S. Postal Service to handle a nationwide influx of mail-in ballots beginning next month?

So far, there’s not much reason for confidence. Last week in New York City, the Board of Elections threw out more than 84,000 mail-in ballots for the June 23 Democratic primary. That was out of a total of nearly 319,000 mail-in ballots, which means...