Trump Is Hobbling the Mail the Old-Fashioned Way

On the eve of a highly consequential presidential election, when millions of citizens are eager to protect their health by voting by mail, the United States Postal Service bears the burden of expediting a secure election free of partisan tampering. But the officials with power over the agency appear bent on doing exactly the opposite—that is, returning to an old tradition of politicizing the post.

President Donald Trump has denigrated Americans’ favorite government service as “a joke,” and his administration has explored ways to limit mail-in voting—which the president has...