Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds.

A barking dog, apparently, is another matter.

Last week’s decision by the Postal Service to force more than two dozen residents of the first three blocks of N. Roosevelt St. to install rural mailboxes because of a complaint about a single unchained dog at one of the residences is the latest in a series of ridiculous power grabs by tin-earred federal bureaucrats.

The Postal Service admits that only one dog is involved. It has been coy about how many times the dog has been a problem — only that it was “more than once.” Twice? Three times? A thousand? It’s unclear.

What is clear is that it’s never been so much of a problem that police were notified. Nor has any rationale been offered for why more than two dozen residents have to pay for the sins of just one owner who can’t keep his dog at home.

If all this is being done to ensure safety, it surely will have the reverse impact.

As letter carriers cruise down the street in comfort, residents — including the infirm —will have to assume the perils of snow, rain, heat, gloom of night, and one particular dog.

That’s good news for Fido. He no longer will have just one target a day. He’ll have two dozen or more — a clear win for him and for potential identity thieves; a clear loss for commonsense.

Forget concerns about WiFi. It’s not the safest thing in the world to leave your most confidential communications in a box near your front door, but it’s a level of magnitude more dangerous to leave them in a box along the street, a small hike from where you might hear someone breaking in.

In recent years, the Postal Service — particularly locally — has been hyper-aggressive in moving as many local customers as it can from home delivery to street delivery.

It probably saves postal workers a lot of grief and the Postal Service a ton of money. But it comes at a price. Installing a new rural mailbox will cost each resident more than they spend, for example, on a subscription to this newspaper.

If the Postal Service needs to save money to pay for Rube Goldberg sorting machines at its regional centers, which seem to do nothing but delay delivery of wanted publications to distant readers, it should be honest about it — and not blame Fido when it really wants to stop walking mail door to door.

At least give Fido his day in court — or, rather, give Fido’s owner a day in court to justify why he or she can’t follow straightforward city code and keep Fido from running at large.

Instead of “fining” two dozen residents by requiring them to install rural mailboxes, a single $70 fine to the owner of the one dog involved might do the trick — if, in fact, this really is about protecting letter carriers and not about making their jobs cushy.

That old saying about snow and rain dates to 500 years before Christ and described mail delivery in Persia. It’s unfortunate that what has been a standard of a noble profession for 2½ millennia can be so easily overturned by a single barking dog.

Cats of the world might be justifiably jealous of such power. Then again, those of us who own them have long known they would be great candidates for working as bureaucrats.

— ERIC MEYER